PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.
This PDF file contains the front matter associated with SPIE Proceedings Volume 10313, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The nonlinear nonperturbative response of atoms in intense laser fields has been extensively studied both experimentally and theoretically in the past twenty years leading to new unexpected effects such as Above Threshold Ionization, ATI, high order frequency generation etc. and these are documented in recent book The similar studies of molecules is a new chapter in the pursuit of laser control and manipulation of molecules. The nonlinear nonperturbative response of molecules to intense (I<1015 W/cm2 ) and ultrashort (V10 fs) laser pulses [2] is expected to yield new effects due to the extra degrees of freedom nuclear motion as compared to atoms [3], such as creation of Laser Induced Molecular Potentials, LIMP' s, Charge Resonance Enhanced Ionization, CREI [4] and molecular High Order Harmonic Generation [5]. These nonlinear nonperturbative in effects were seen in experiments [6] and were predicted and confirmed by high-level numerical simulations of appropriate time-dependent Schrodinger equations [3-5,7], TDSE's, of molecules in laser fields. Our recent supercomputer simulations of H2+ molecule dynamics in intense laser fields, [7-9] based on TDSE, also allowed us to propose two new molecular imaging techniques: a) LCEI, Laser Coulomb Explosion Imaging [8] and b) LPEI, Laser Photoelectron Imaging [9]. The first is based on the analysis of the kinetic energy of molecular fragments after Coulomb Explosion, CE, whereas the latter imaging uses the shape of ATI electron peaks, produced by an intense laser pulse. We describe summarily in the present communication these two imaging methods which were developed using high level supercomputer simulations
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Femtosecond laser technology based on pulse stretching-compressing technique has been demonstrating tremendous achievements [1], but it is still complicated and expensive. In this report we present a new generation of simple and robust high peak power diode-pumped Raman lasers. They are capable of producing laser pulses in picosecond range with pulse repetition rate (PRR) from f=10 Hz to f=7.5 kHz. Passat Ltd. has recently developed Raman lasers operating in three PRR formats: low PRR (1 - 25 Hz), medium PRR (100 Hz - 1 kHz), and high PRR (2.5 - 7.5 kHz). Table 1 shows parameters of Raman lasers supplied with harmonic generators for each of the PRR formats specified above.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Laser ultrasonic measurements are emerging as an efficient means for remote probing of metals. This technique offers the possibility to perform non-contact measurements in a hostile environment, at high temperature, and on any kind of structure. There are two regimes for generating ultrasound in a metal: thermo-elastic and ablative. The former, uses low-energy laser pulses to heat the surface of the sample. The transient expansion of the near surface region launches compression waves into the sample. These displacements are very small (-10 pm) in metals because of the low optical penetration depth, such that lock-in detection techniques must be used for these measurements. In the ablative regime, a higher energy density laser pulse causes partial ablation of the target surface and ionisation of the ablated material. The plasma thus created can reach very high pressures, which causes the plasma to accelerate away from the surface and launches a compressive elastic wave into the sample. The amplitude of these waves is much greater (-10 nm) than those generated in the thermo-elastic regime and they can easily be measured by single shot interferometric techniques. Theoretical simulations of ablation by ultra-short laser pulses [F.Vidal et al., PRL, 86, 2573 (2001)] explore the generation of high frequency ultrasound waves (- GHz) in a thin aluminum film. These simulations indicate that the ultrasonic pulse duration is proportional to the laser pulse duration down to 100 ps, and that below 100 ps, further reduction of the laser pulse duration has little effect on the ultrasound pulse duration.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In order to study ultrashort laser-produced plasmas, we developped at INRS a subpicosecond x-ray streak camera, called the PX1. The PX1 has been completely characterized.' Using an extraction field of 250 kV/cm, a record 350 fs temporal resolution has been measured with x-ray pulses in the KeV range. Also, we obtained a 40 tim spatial resolution along the 15 mm slit of the photocathode in single-shot. The PX1 has also been used in accumulation mode and a temporal resolution of 800 fs has been obtained with unlimited dynamic range. Recently, in an effort to improve upon these results, a new x-ray streak camera has been developped and tested. This camera, called the FX, uses the new generation of bilamellar tube technology. This includes a better control of the paraxial trajectories, a larger quadripolar lense to increase the usable width of the photocathode and a new design of the electronic lenses to permit the use of higher voltages.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Many oxides undergo insulator to metal phase transition. For example, eight vanadium oxides undergo such a transition. The transition of vanadium dioxides (V02) was first reported in 19591 and has been characterized by several different means. Recently, the developments of femtosecond laser technologies have made possible time resolved studies of this phase transition. The purpose of this study is to investigate the correlations between electronic and atomic dynamics during the phase transition as a function of the laser conditions and the physical properties of thin films of V02. These experiments were realized in two steps: in the first step, we characterized the visible response of the samples. The structural dynamic of the phase transition using time resolved x-ray diffraction has been studied in a second step.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Femtosecond laser have been useful in the optical domain to understand the dynamics of ultrafast system. However, theses techniques only yield indirect information on the structural change. The extension of the pump-probe technique to the x-ray can provide at the same time, temporal and structural information, giving a molecular movie of a chemical reaction.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We describe a hybrid semiconductor saturable absorber mirror (SESAM) structure that has been developed as a passive mode-locking element for use with Cr:YAG, and other low gain laser systems. In addition to describing the device and its fabrication we report the results of initial mode-locking experiments carried out with a Cr:YAG laser. Mode-locked pulses as short as 500 fs have been generated.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We have developed a high intensity, dual-wavelength laser system to carry out vibrational excitations of molecules via mid-infrared radiation [1] or Raman Chirped Adiabatic rapid Passage (RCAP) [2,3]. We have previously reported amplifying two outputs from a dual-wavelength, mode-locked Ti:sapphire laser to a total energy of 1.5 mJ, in a single regenerative amplifier [4]. Also we have reported the generation of 1.5 ILI pulses at 10 [an, from mixing the output of the two colour amplifier [5] . In this report, we describe a dual-wavelength, multi-pass amplifier, that increases the energy of the two pulses to a combined level of 15 mJ. The two pulses can be used directly in an RCAP experiment or be difference frequency mixed to generate high intensity mid-infrared radiation, for the chirped mid-infrared experiment. We have now increased the energy to 7.4[0, by using 4.7 mJ of energy from the multi-pass amplifier.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Introduction Mass spectrometers are used to determine the masses of atoms, molecules, and clusters in a wide range of applications. Presently, there is a drive towards the miniaturization of such devices for use in spacecraft life support, pollution monitoring, and explosives/narcotics detection applications. For a given mass resolution, the ion flight distance (and hence the size) of a time-of-flight (TOF) mass spectrometer is related to the length of the ionization region along the flight axis. Since femtosecond pulses can ionize atoms and molecules within a very small focal volume with near unit efficiency, they are compatible with miniature mass spectrometers. We have demonstrated a general technique for compact TOF mass spectrometry using two spatially separated laser foci. The first femtosecond laser pulse ionizes a gaseous sample and the second pulse probes for the presence of a specific mass in the analyte. Our approach enables TOF mass analysis to be performed on a sub-millimetre length scale. Furthermore, the second pulse can be intense enough to explode the molecules it probes. Using such laser- induced Coulomb explosion for molecular detection yields a significant improvement in detection efficiency for large molecules. Taken together, these developments can reduce the size and complexity of miniature TOF mass spectrometers and allow the fabrication of integrated mass analyzers with relaxed voltage, vacuum, detector, and timing electronics requirements.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Semiconductor diode lasers can provide compact sources of ultrashort light pulses [1-2]. Our research efforts are aimed at the development of a widely tunable, diode laser source for the generation of picosecond, and ultimately sub-picosecond, pulses. The InGaAsP/InGaAs active region of the diode is composed of two quantum wells [3-4] grown lattice matched to GaAs. Work is done using both symmetric and asymmetric structures. All laser structures are grown using the McMaster molecular beam epitaxy facility. Mode-locking is achieved with the diodes in an external cavity configuration. The two different quantum wells allow a 64 nm tuning range centered at 985 nm. Typical pulse durations measured directly from the diode are found to be between 3 and 15 ps. The mode-locked output from the external cavity laser is then coupled into a semiconductor optical amplifier to increase the pulse power. The active regions of the amplifiers are based on the same InGaAsP/InGaAs material as for the oscillators. Our initial amplification work focuses on narrow stripe geometries. This provides large bandwidth, single pass traveling wave amplification. The effect of amplification on pulse shape is measured using a cross-correlation technique. In this technique, the ps pulses are frequency mixed through a nonlinear crystal with 80 fs, 795 nm pulses from a mode-locked Ti: Sapphire laser.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The enhanced ionisation thresholds for the triatomic OCS molecules have been determined using a classical model. By using these thresholds to determine the dissociative motion of an OCS molecule in a 55fs laser pulse of intensity 2x10'5 W/cm2, the accuracy a Coulomb imaging experiment has been quantified.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Femtosecond lasers have proven to be very useful tools for the microstructuring of solid targets [1, 2, 3]. The ablation of metals using conventional lasers is accompanied by formation of substantial heat-affected zones. Extremely fast energy deposition and rapid ablation with small heat-affected zones make it possible to achieve controllable ablation and production of high-quality structures in metallic materials. A significant improvement in this field has thus become possible because of ultrashort pulse lasers. With ultrashort-pulse laser systems, measurements of laser-induced damage and ablation thresholds on metals have been performed for both a very broad range of pulse durations and wavelength regions. Comprehensive ablation experiments of metals such as Cu, Al, Fe, Au, and Ag by using solid state and excimer femtosecond have been reported [1-5]. In this study, we investigated the effects of femtosecond laser irradiation on metals via study of scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The recent discovery of superconductivity at 39 K in magnesium diboride, MgB2, [1] stimulated extensive research of this material's physical properties and future applications in superconducting electronics and optoelectronics. We report here our studies on optical photoresponse of superconducting MgB2 thin films using the femtosecond pump-probe spectroscopy [2,3]. In pump-probe experiments, the output of an ultrafast laser is divided into two beams. One beam is used to excite the sample. Since the pulse duration is only -100 fs, it acts as a delta-function-type excitation. The second beam probes the changes induced by the excitation, usually either as the relative change of reflectivity or transmissivity by as a function of the relative time delay to the pump beam. The probe beam is much weaker than the pump beam to ensure that the changes in the material are induced only by the pump beam. With femtosecond spectroscopy, we are able to study the dynamics of electrons and the electron-phonon interaction with subpicosecond resolution. In our experiments, a commercial Ti:Sapphire femtosecond laser with 76 MHz repetition rate is used to generate 100-fs-wide, 800-nm-wavelength optical pulses.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
NbN superconducting single-photon detectors (SSPDs) are very promising devices for their picosecond response time, high intrinsic quantum efficiency, and high signal-to-noise ratio within the radiation wavelength from ultraviolet to near infrared (0.4 gm to 3 gm) [1-3]. The single photon counting property of NbN SSPDs have been investigated thoroughly and a model of hotspot formation has been introduced to explain the physics of the photon- counting mechanism [4-6]. At high incident flux density (many-photon pulses), there are, of course, a large number of hotspots simultaneously formed in the superconducting stripe. If these hotspots overlap with each other across the width w of the stripe, a resistive barrier is formed instantly and a voltage signal can be generated. We assume here that the stripe thickness d is less than the electron diffusion length, so the hotspot region can be considered uniform. On the other hand, when the photon flux is so low that on average only one hotspot is formed across w at a given time, the formation of the resistive barrier will be realized only when the supercurrent at sidewalks surpasses the critical current (jr) of the superconducting stripe [1]. In the latter situation, the formation of the resistive barrier is associated with the phase-slip center (PSC) development. The effect of PSCs on the suppression of superconductivity in nanowires has been discussed very recently [8, 9] and is the subject of great interest.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photoconductive devices based on various semiconductor materials such as ion-implanted InP,1' 2' ion-implanted silicon-on-sapphire,3 amorphous silicon and low-temperature-grown GaAs (LT-GaAs),`-7 as well as metal- semiconductor-metal diodess have been under investigation to generate picosecond and subpiconsecond electrical pulses for the last two decades. Those photoconductive switches, however, suffer from a difficulty to integrate them with optoelectronic circuits due to their nonstandard active materials. The hybrid integration unavoidably reduces their intrinsic multigigahertz bandwidth. We present here a new method of making a freestanding LT-GaAs photoconductive switch, which can be placed at virtually any place of the circuit containing a coplanar strip (CPS) transmission line. We also demonstrate that the freestanding LT-GaAs photoswitch exhibits a subpicosecond photoresponse time.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Superconducting detectors become the most prominent technology for radiation sensors with ultimate performance. Typically, they are nanostructures formed from an ultra-thin superconducting film incorporated into an external antenna for efficient radiation coupling. The operation of so-called hot-electron bolometers and photodetectors (HEBs and HEPs) is based on nonequilibrium heating of the electron subsystem by the absorbed radiation and results in the film resistance and a corresponding, easily measurable voltage response when device is current biased [1-2]. A relatively simple, single-layer manufacturing technology made these devices very popular for needs of radioastronomy and remote sensing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Josephson-junction-based low temperature rapid single flux quantum (RSFQ) superconducting electronics is already a mature technology, which is expected to perform at speeds exceeding 100 GHz [1]. However, the RSFQ technology still lacks a fast enough output interface between its operating circuit temperature T = 4.2 K and the room temperature electronic environment. RSFQ circuits work at liquid helium temperatures and the direct interconnection of these circuits and room temperature circuits using, e.g., copper transmission lines would consume too much of the cooling power [2]. To solve this problem a magneto-optical (MO) output interface has been proposed [3], in which the output current pulse from the RSFQ circuit is converted into an optical pulse and delivered to room temperature readout circuitry via an optical fiber.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Canadian community propose to establish a Canadian based International Research Facility that will explore a completely new approach to dynamic investigation of matter. The basic goal is to provide the research community with tools to image changing molecular structures. The approach will be based on recent advances in ultrafast technology to provide a new generation light source for molecular imaging. The facility, called the Advanced Laser Light Source (ALLS), will enable the combination of any or all of the most advanced laser technologies for exploiting light-matter interactions. This facility will bring together some of the most outstanding researchers in biology, chemistry, and physics around Canada and the world to work collectively towards this vision.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The frequency downshifting of fundamental laser output via stimulated Raman scattering has been previously demonstrated and studied mainly with flash-lamp pumped Q - switched Nd:YAG lasers [1,2]. With the advent of diode - pumped lasers it was an issue of time when the technique of Raman conversion would be applied to such lasers. Recently there appeared a number of publications in which Raman lasing is reported in diode - pumped lasers (see, for example [2-4]).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Neptec Design Group has developed the Laser Camera System (LCS), a new 3D laser scanner for space applications, based on an auto-synchronized principle from the National Research Council of Canada (NRC). The LCS was tested in August 2001 during mission STS-105 of the space shuttle Discovery to the International Space Station'.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Neptec Design Group has developed a Laser Camera System (LCS) that can operate as a 3D imaging scanner. The LCS uses an auto-synchronized triangulation scheme to measure range information while two orthogonal scanning mirrors sweep through the field-of-view. The LCS simultaneously records intensity of the reflected laser beam and range information. The intensity data can be used to produce 2D grayscale images as well as to map the intensities onto 3D surface models. The nature of triangulation geometry dictates that such measurements are best for close objects, with range error increasing with the square of object rangel. The LCS was flown in the payload bay of the shuttle Discovery during mission STS-105. Four scans were taken of the same scene while the shuttle was docked to the International Space Station (ISS)2. Partially visible ISS elements included the SSRMS (Canadarm2), Multi-Purpose Logistics Module (MPLM), Destiny Lab Module, Node 1 (Unity), Joint Airlock Module (Quest), and several solar arrays.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Neptec Design Group has developed the Laser Camera System (LCS), a new 3D laser scanner for space applications, based on an autosynchronized principle from the National Research Council of Canada (NRC). The LCS operates both in imaging and target centroid acquisition modes. In imaging mode, the LCS raster scans objects and can produce 2D and 3D maps of their surface features. In centroid acquisition mode, the LCS determines the position of discrete target points on an object. The LCS was tested in August 2001 during mission STS-105 of the space shuttle Discovery to the International Space Stations. From a fixed location in the shuttle payload bay, the LCS 1500 nm eye-safe infrared laser was pre-programmed to draw Lissajous patterns on Inconel (black dots on a white background) and retro-reflective disc targets affixed on the Multi-Purpose Logistics Module (MPLM). The LCS acquired centroid data for two and a half hours during the MPLM demating operation to demonstrate its ability to track both types of targets when they are stationary and moving.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Introduction The fully integrated Advanced Camera for Surveys (ACS) (Ford et al. 1998, SPIE Vol. 3356, 234), suc- cessfully installed in the Hubble Space Telescope (HST) in early March 2002, underwent a series of ground calibration tests at Ball Aerospace and Technologies Corporation (BATC) and at the Goddard Space Flight Center (GSFC) to verify its performance and flight readiness (Hartig et al. 1998, SPIE Vol. 3356, 321). The flight build detectors were installed in late 2000 and the majority of the flight quality data were acquired in the following year. The activities revolved around several major campaigns designed to characterize the flight build detectors and the optical and ultraviolet channels of the instrument and to verify the contract-end-item specifications. In the following, we briefly describe the different ground-based activities.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Over the past five years the feasibility of spaceborne differential absorption lidar (DIAL) systems for the purposes of trace gas monitoring in the atmosphere has been studied [1,2,3]. The feasibility of such instruments is supported by the results of studies such as ORACLE (Ozone Research with Advanced Cooperative Lidar Experiment: a joint study of NASA/LaRC and the Canadian Space Agency) and WALES (Water vApor Lidar Experiment in Space: a study by the European Space Agency). One crucial aspect determining spaceborne DIAL performance is the collecting telescope's aperture size. In this respect, the interests of the atmospheric remote sensing and the astronomy communities overlap, in that spaceborne telescope aperture size is a key performance driver for both applications. While the stringent optical performance requirements characteristic of astronomical instruments -and the success seen in reaching some of these goals for the Next Generation Space Telescope (NGST)- are encouraging for the realization of more modest spaceborne lidar telescope optical performance requirements, spaceborne DIAL telescope development nevertheless provides its own challenges.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
SWIFT Objectives The primary objective of SWIFT Explorer is to provide high resolution global measurements of horizontal winds in the stratosphere for both day and night. Furthermore, SWIFT will measure the stratospheric ozone concentration co-located with the wind. The specific scientific objectives are tropical wind climatologies, transport studies and data assimilation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The National Research Council of Canada, Herzberg Institute of Astrophysics has been developing a reconfigurable slitmask intended for the NGST near IR spectrograph. The Mechanically Actuated Reconfigurable Slitmask (MARS) creates 50 slits in the telescope focal plane. The slit location and width are adjustable, but the height is fixed. Reconfiguration of the mask components is achieved using a combination of electromagnetic and piezoelectric actuators. This actuation scheme has undergone structural, electrical, thermal and magnetic analysis. Several prototype components have also been built and tested. This analysis and testing indicates that the MARS device represents a viable concept for creating slits within the NGST near IR spectrograph.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The CALTRAC® star tracker is a space-borne attitude sensor, that uses a wide-angle all-reflective telescope with a highly curved image surface and a small f-number. There are a number of critical optical metrology activities that are involved in building the star tracker. These include, among others, aligning the optics and CCD detector subassemblies to form an optics head by using a five-star simulator, measuring angles between internal optical axes and external references for space-craft integration, positioning the vertex of the optics to the rotation axis of a 2D rotary table for subsequent optical calibrations, determining the lateral location of an internal CCD baffle, and verifying the precision of the 2D rotary table to arc- second accuracy. Optical measurements involved in these activities must be performed accurately, so as to ensure the overall performance of the integrated star tracker system. This paper is intended to introduce the methods of optical measurement that were developed for these purposes. Accuracy achieved with these methods has proven sufficient in supporting the development and production of the star trackers.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Next Generation Space Telescope project in its early definition phases has given birth to many innovations in instrumentation for astronomy by providing funding for industries in an area often considered less lucrative and hence of lower interest. New alliances were formed with universities and institutions and the knowledge exchange lead to very interesting new concepts. The Imaging version of the Fourier Transform Spectrometer (IFTS), a derivative of the classical Michelson interferometer that has been used successfully in spectroscopy for decades, was introduced in military applications in the mid 80's with small FPA (- 2 X 4).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Optical design is both an art and a science. There is any computer program that will create lens design without guidance from an optical designer. Understanding the engineering trade-offs will help you choose the right lens design for your application. With the increasing complexity and precision of space-based and astronomical optical system, the effects of the environment upon optical system reliability are becoming more important. Some phenomena pose potential threats to the success of optical instruments. We present some of them.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Liquid mirrors are an established technology; they have proven to be a viable low cost alternative to conventional glass optics in several applications. We are working to expand the capabilities of liquid optics by developing a material that can be deformed rapidly in a precise manner as is the case for conventional solid optics while maintaining the low cost and relative ease of construction of current liquid mirror devices. In this paper we discuss the application of a new ferrofluid based technology to the problem of deformable mirrors in adaptive optics.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This work forms part of The Hyperspectral Mission (THM) program, funded by the Canadian Space Agency. The designs correspond to three mission profiles with the parameters listed in Table 1. Two of the potential missions are designed for a flight on the EXPRESS external pallet of the International Space Station (ISS). All designs make use of push-broom imaging, whereby a slit is scanned across the scene by the orbitiil motion of the platform. In the case of the Enhanced ISS and Small Satellite designs there is an option to use ground motion compensation to reduce the ground sampling distance. There is also a common requirement for all the designs for a 0.4ftm to 2.5pm spectral waveband but there are varying requirements for instrument field, spatial and spectral resolution.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Instrument Group at the Dominion Astrophysical Observatory (DAO) is a group of engineers and specialists whose main work is the design, production, and testing of instrumentation for large astronomical telescopes. Areas of expertise include electronic, mechanical, optical, and software engineering. Some notable instruments that have been completed are the adaptive optics system for the Canada-France-Hawaii 3.6-metre telescope (CFHT) and a multi-object spectrograph for the Gemini North 8-metre telescope, both on Mauna Kea in Hawaii. Projects now being designed or built include a second multi-object spectrograph for Gemini South in Chile, an adaptive optics system for Gemini North, components for a wide-field camera for CFHT, and preliminary design of components for an adaptive optics system for Gemini South. Because of the operating environment of the instruments and the precise tolerances required for optical alignment, these instruments produce unique design problems that need to be solved to meet instrument specifications. The following summary is a description of the methods developed for the mounting of lenses and mirrors.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Herzberg Institute of Astrophysics (HIA), AMEC Dynamic Structures Ltd. and several other Canadian university groups are currently in the initial phases of designing a new 20-25 metre class, ground-based, optical telescope called the Large Optical Telescope (LOT). At more than six times the collecting area of current state-of-the-art telescopes, the LOT will enable Canadian astronomers to continue carrying out forefront astronomical research. However, the LOT presents difficult design challenges not encountered with previous observatories. The successful design, construction and operation of the LOT will not only require detailed studies of all major telescope subsystems but will also require a fully integrated model of the entire observatory.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A nanosatellite controUcommunications concept is described using a 'state machine' control paradigm and optical communications to dramatically reduce the mass and power consumption for payloads that can tolerate a low, intermittent data rate.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The paper reports on recent progress in electro-optical and photonics developments at the Canadian Space Agency / Space Technologies / Optical Instrumentation Group. Technology R&D projects in active sensing, lasers and Optical Inter-Satellite Links (OISL) are underway both in-house and in contracting out to Canadian industry. In-house projects are concerned with: - Research and development of a novel all-optical tracking technique for OISL using non-linear optical concepts; these include development of a high-speed communication interface and search for efficient non-linear / optical / laser / light-weight materials to work in the space environment. - Development of space vision systems - an eye-safe laser scanner for 3D-tracking and imaging, and a stereo vision system for object recognition and pose tracking linked to a robotic test-bed (in cooperation with CSA Spacecraft Engineering / Robotics Group); CSA has supported the development of a laser vision system that was demonstrated on a recent Shuttle flight.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The infrared astronomy group at the Universite de Montreal has been involved in building instruments for the past 20 years, to support its own research projects or under contract with the Canada-France-Hawaii Telescope Corporation and the National Research Council. A camera for the detection of faint objects around nearby stars, a multiobject spectrograph for the 0.8pm to 2.5pm spectral range, and a wide field camera, funded by the Natural Sciences and Engineering Research Council and the Canadian Foundation for Innovation, have been designed recently and are described below. The triple-imager Trident
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Research in organic solid and polymer-based optoelectronic devices is driven by the physical flexibility, low cost, processability, and almost infinite spectrum of functional possibilities offered by organic materials. Many active components currently used in fiber-optic communication system reply on the use of inorganic semiconductors and mechanical means, which makes each of the components bulky, rigid and independent. Photonic on-chip integration is extremely difficult with current components and materials. Thus, there is a need for a new and emerging class of organic materials for use in a range of important optoelectronic components, which enables improvement and revolution in device performance, device miniaturization and on-chip integration.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Recently we have started a project on a new type of azobenzene polymers, namely azobenzene elastomers (AEs). Our purpose is to investigate the coupling effects between mechanical stretching and photoisomerization of azobenzene and to explore the potential of using azobenzene elastomers for mechanically tunable optic or photonic devices. The polymer shown below is such a thermoplastic elastomer that is obtained by grafting an azobenzene side-chain liquid crystalline polymer (SCLCP) onto a styrene-butadiene-styrene triblock copolymer (SBS).1 The concentration of the azobenzene-SCLCP ranges from 10 to 20 wt %.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We have synthesized azobenzene-containing chiral gelators for liquid crystals (LCs), two of which, AG1 and AG2, are shown below. When dissolved in a LC host, driven by intermolecular hydrogen bonding, the gelator molecules are able to gel the LC through the formation of fibrous aggregates that lead to a non- covalent network. A variety of interesting phenomena were observed for this new type of functional materials.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Recently, there has been much attention focused on photonic crystals and photonic bandgap materials [1]. The fabrication of these materials requires the formation of a periodic variation in the refractive index on a submicrometer length scale. It is anticipated that these structures will provide the building blocks required for future photonic devices and photonic integrated circuits. Applications are envisaged for structures with both 2- and 3-dimensional periodicity. In this communication we report results from a novel variant of ion beam lithography. The approach involves ion implantation through a mask of silica microspheres, followed by selective chemical etching.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We have studied the dynamics of photocarriers in doped InAs/GaAs self-assembled quantum dots using time- resolved photoluminescence measurements. The influence of the excitation conditions (excitation power, wavelength) and the effect of the doping level have been investigated. The rise time of the quantum dot emission signal is correlated with the number of carriers inside the dots whether they are introduced by doping or by photoexcitation. In both cases, the photoluminescence rise time diminishes with the number of carriers. A four-level model taking into account different interlevel relaxation and capture mechanisms has been used for the simulations of the photoluminescence transients. Discussion on the physical hypothesis behind this model is given.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The nonlinear optical properties of mixed (merocyanine dye + fatty acid) Langmuir-Blodgett multilayers were investigated using second-harmonic generation for possible device application. The influences of the dye concentration and the number of monolayers on the intensity and the spectral shape of the second harmonic signal are reported.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Organic materials suitable for application in electronics (e.g., thin film transistors and) and optoelectronics (e.g., light emitting diodes) have received increasing attention during the past years. Such new compounds are not designed to replace the existing technology where speed and stability under extreme conditions are vital. These compounds could be potentially used for applications that require short-term use and large- scale manufacture. Of great interest as novel materials are substituted pnetacenediquinones for optoelectronics applications, substituted pentacenes for thin film transistors and indenofluorene derivatives for applications in light-emitting diodes. Pentacenediquinones are compounds that contain five aromatic rings in a row and two quinoid moieties in their structure. Pentacenediquinones can be easily reduced electrochemically to the corresponding semiquinone (radical anion). The semiquinone displays absorbance in the near-infrared (NIR) region, between 1300 and 1500 nm.1'2 By introduction of various substituents on the two "outside" aromatic rings (figure 1), the semiquinones of substituted pentacenediquinones offer a possibility to fine tune the MR activity in the three telecom windows: 1550, 1310 and 880 nm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A series of linear and hyperbranched poly(ether imides) containing diacetylene moieties are synthesized. Control of refractive index of the polymers can be achieved by varying the ratio imide/ether content. For the linear polymers the in-plane refractive index (nm) at 1550nm can be tuned between 1.5454 and 1.6313 by changing the ratio of two monomers. The maximum value is reached at 100 mol% of the imide monomer. The arm value can also be controlled between 1.5329 and 1.6283 by varying the monomer ratio. Decrease of birefringence was obtained by increasing the ether monomer content, from 1.25x10-2 to 3x10-3. The refractive indices of the hyperbranched polymers vary from 1.5646 to 1.6263 for nm and from 1.5584 to 1.6277 for nm. The chain branching causes a significant reduction of the birefringence to as low as 2x104 for polyTPPE and 6.2x10-3 for the hyperbranched poly(ether imides). UV curing of the thin polymeric films produces small changes in both nm and aim, lowering their value with an average of 5.5x10-3. Thermal curing produces coloration of the films, with an increase in refractive indices, both nm and arm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
With the increasing growth of semiconductor and photonics technology, the optical materials have attracted considerable attention since they can meet the demanding performance requirements for the telecommunication, data communication and information storage systems.1'2 One of the most interesting and fast-developing classes of optical materials is optical polymers, which show promising over silica and semiconductors as a platform technology for photonics integration in that optical polymers are able to provide increased functionality, rapid fabrication, much efficient power and furthermore they have the potential to facilitate next-generation hybrid active/passive devices.3'4 To achieve high level of photonics integration, planar waveguide technology is considered to represent one of the more significant technologies of the next decade that paves the path with innovative polymers, hybrid materials and low- cost integrated optical components, as well as brings about substantial advantages in some issues such as labor cost, component density and optical loss.5'6'7 A new class of curable optical polymers containing benzocyclobutenone (ca. BCBO polymers) has been developed as waveguide materials for photonic integration.8 BCBO (1) is a latent reactive ketene and readily undergoes thermal and photochemical reactions in quantitative yield with a variety of functional molecules such as an alcohol (Scheme 1).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Recent advances in flat-panel display technology have ignited the search for new powdered phosphors with nanometer dimensions. Currently, phosphors in the micrometer size range find applications in a wide variety of information display devices such as cathode-ray tubes (CRTs), field emission displays (FEDs), vacuum fluorescent displays (VFDs) and electroluminescent (EL) devices [1]. Micrometer sized Y203:Eu3+ phosphors have been used since the 1970's as the red component in television projection tubes and fluorescent lighting devices [2]. It is anticipated that the advent of nano- sized phosphors will lead not only to improved resolution but also to an increase in luminescent efficiency. A class of materials that has shown considerable promise in delivering these qualities are lanthanide doped nanocrystalline materials.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Oxide based glasses have proved to be interesting hosts due in part to their usefulness in the field of photonics. The addition of the tripositive erbium ion to the glass structure in the form of an impurity allows for the use of the glass host as a material for high power lasers and optical amplifiers. Erbium doped oxide glasses show a relatively broad emission band at approximately 1500 nm ascribed to the 4113/2 --< 4115/2 transition. This broadening of the emission band is due to the high degree of disorder inherent in all vitreous materials. Unlike in crystals where the environment of each ion is identical, individual dopant ions in a glass matrix will reside in different sites and thus, the spectra will consist of overlapping contributions from each distinct site. Furthermore, the luminescence lifetime of the 4113/2 state is long (milliseconds) and as such, these glasses are suitable for use as optical amplification devices [1]. For some applications, upconversion can prove to be deleterious and thus, any investigation into the optical properties of Er3+ glasses is not complete without studying its upconversion properties. Upconversion is a phenomenon whereby low energy photons, usually infrared, are converted into photons of higher energy. In this paper, we will present a detailed investigation of the optical properties of an erbium doped sodium phosphoniobate glass.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In modern WDM/DWDM based optical networks, wavelength division is very important. Bragg gratings are used in many devices to reflect, and thus isolate, specific wavelengths of light. Chalcogenide glasses can be used to create such gratings due to photorefractive effects that take place when illuminated with near bandgap light. We have created holographic Bragg gratings in As2Se3 films by using a HeNe laser to illuminate the glass in a periodic interference pattern. Refractive index changes of 0.009 have been measured.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In this paper, we report on the fabrication of Erbium doped waveguide amplifiers (EDWA's) using electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD). The salient process parameters are presented, as are the determination of the Er content through Rutherford Backscattering (RBS), and measurements of the film composition using elastic recoil detection (ERD), nuclear reaction analysis (NRA) and secondary ion mass spectroscopy (SIMS).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Electroluminescence in conjugated polymers was first discovered in poly(p-phenylenevinylene) (PPV)1. Since then research efforts on polymer-based light emitting devices have increased dramatically, primarily due to their potential application in full color flat panel displays and the low fabrication costs associated with this technology. Poly(phenylenevinylene) (PPV) and its derivatives have been widely used as emissive materials in polymer light emitting diodes (PLEDs). Conjugated polymers derive their semiconducting properties from delocalized It- electrons along the polymer chain. Therefore it is possible to modify the semiconducting properties of the polymer by adding different functional groups to the polymer structure thereby altering the extent of delocalization of the rc-electrons. The knowledge of how different functional groups in the PPV structure affect its physical properties is very important for understanding the structure-property relationship in this material. However, a broad molecular weight distribution and the presence of blocks with different conjugation lengths in the polymeric material often complicate the issue. In this sense, oligo(phenylenevinylene) (OPV) type of material is ideal to use as a model system to study the structure-property relationship. Due to controllable and well-defined chemical structures, it is much easier to follow and correlate the physical properties of the OPVs with the molecular structures. In addition, many oligomeric materials can be thermally sublimed under high vacuum, allowing for the preparation of multilayer organic light emitting diode (OLED) structures and devices in an ultra-clean and well-controlled environment thus overcoming the uncertainties involved in wet processes.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper describes a virtual private optical network architecture (Optical VPN - OVPN) based on virtual router (VR). It improves over architectures suggested for virtual private networks by using virtual routers with optical networks. The new things in this architecture are necessary changes to adapt to devices and protocols used in optical networks. This paper also presents information models for the OVPN: at the architecture level and at the service level. These are extensions to the DEN (directory enable network) and CIM (Common Information Model) for OVPNs using VRs. The goal is to propose a common management model using policies.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Telecommunication transmission systems continue to evolve towards higher data rates, increased wavelength numbers and density, longer transmission distances and more intelligence. Further development of dense wavelength division multiplexing (DWDM) and all-optical networking (AON) will require ever-tighter monitoring to assure an agreed quality of service (QoS), characterized by network availability and bit-error rate (BER). However, it becomes complex with traditional methods when applied in next generation networks. For the purpose of obtaining information quickly and accurately in future transmission systems, new monitoring schemes need to be developed and deployed. The paper provides a view of next generation monitoring requirements, business drivers as well as performance monitoring techniques, potentially applicable as next generation performance surveillance methods.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Normalized laser rate equations suitable for large signal analyses are discussed. A large signal laser model suitable for system level simulations is presented. Predicted laser modulation response characteristics are given for Fabry-Perot lasers and compared to measured results. The dependence of the laser modulation response on the laser relaxation-oscillation peak frequency and laser biasing is predicted and compared to measured values. It is demonstrated that the small-signal carrier modulation bandwidth is limited mainly by the intensity dependence of the modulation frequency and the laser's damping rate of oscillation. Simulated and measured results demonstrate that the relaxation-oscillation peak frequency is a reasonable estimate for the modulation bandwidth, and the variation of the modulation response with the output power is nearly flat at fixed modulation frequencies.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The dramatic growth of the Internet and the optical core network that supports it has recently slowed down in spite of a growing appetite for bandwidth-hungry services and applications, particularly those with video content. One of the major reasons for the pause is the lack of affordable broadband access transport facilities extending optical rate connectivity over the last mile.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The transmission of information as optical signals encoded on light waves traveling through optical fibers and optical networks is increasingly moving to shorter and shorter distance scales. In the near future, optical networking is poised to supersede conventional transmission over electric wires and electronic networks for computer-to-computer communications, chip-to-chip communications, and even on-chip communications. The ever-increasing demand for faster and more reliable devices to process the optical signals offers new opportunities in developing all-optical signal processing systems (systems in which one optical signal controls another, thereby adding "intelligence" to the optical networks). All-optical switches, two-state and many-state all-optical memories, all-optical limiters, all-optical discriminators and all-optical transistors are only a few of the many devices proposed during the last two decades. The "all-optical" label is commonly used to distinguish the devices that do not involve dissipative electronic transport and require essentially no electrical communication of information. The all-optical transistor action was first observed in the context of optical bistability [1] and consists in a strong differential gain regime, in which, for small variations in the input intensity, the output intensity has a very strong variation. This analog operation is for all-optical input what transistor action is for electrical inputs.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Directly modulated lasers at 1310 nm are useful as low cost short haul high speed transmitters. High speed requires large differential gain and high damping. Low cost dictates that the device can operate without a thermoelectric cooler (TEC) to temperatures of 85 C, preferably without introducing exotic designs or material features. A multiple quantum well (MQW) ridge waveguide (RWG) gain coupled (GC) distributed feedback (DFB) InGaAsP laser grown by metal-organic chemical vapor deposition (MOCVD) satisfies the above requirements.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The technique of quantum well intermixing (QWI) involves intentionally causing interdiffusion between atoms in the quantum wells (QWs) and atoms in the barriers of a QW heterostructure. This interdiffusion alters the compositional profile of the QW, which changes the quantum confinement potential, and which subsequently blueshifts the bandgap and lowers the refractive index of the QW active region. There are several different methods of QWI, all of which allow one to interdiffuse selected regions of a wafer, such that devices with different bandgaps can be monolithically integrated. QWI has been touted as an invaluable tool for the integration of photonic devices. QWI of InP-based heterostructures has been studied since the early 1990s in academia, and it has more recently made a transition into a manufacturing setting, with at least three companies currently pursuing it (Nortel Networks, Intense Photonics, and DenseLight). This paper will discuss some of the key aspects of QWI in a manufacturing process, including a critical review of different QWI techniques, and discussion of realistic device applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Waveguides fabricated from highly transmissive optical polymers have been used for many of applications such as thermal switches [1] and arrayed waveguide gratings [2]. We are presently exploring passive polymer waveguides for the purpose of flexible interconnects between optoelectronic components (also known as optical wire bonds).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The interest in linear amplifiers for metro DWDM networks has resulted in a number of products, including erbium-doped fiber amplifiers, erbium-doped waveguide amplifiers, and gain-clamped semiconductor optical amplifiers (SOAs). An alternative approach is to use a conventional SOA in the unsaturated regime. This paper describes some of the design tradeoffs inherent in such an approach; crosstalk and chirp measurements for two different quantum-well designs are also presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Short haul applications at 1310 nm require modulated sources with low cost, high performance and small footprint. Our activities target the performance aspects of direct modulation design. We demonstrate a fully packaged laser diode able to deliver a data throughput of 20 Gb/s with 6 dB of extinction ratio under a 3 V peak-to-peak modulation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Wireless communications has entered a new phase. The focus is shifting from voice to multimedia services, which need wideband radio links. Furthermore, new wireless subscribers are signing up at an increasing rate demanding more capacity. Micro and pico cellular architecture is an attractive solution for both of these issues because, it increases the frequency reuse and enables wideband access. In this micro/pico cell scenario, low power radio access points (RAP's) should provide wireless access instead of conventional base stations for cost considerations. These radio access points should be robust and have low complexity and connected to the central base station via radio-over-fiber (ROF)1 links [1]. Figure 1 (left) shows such architecture and Figure 1 (right) gives a closer look at the downlink. The focus of this work is to investigate various signal processing strategies to provide a cost-effective, high performance solution for high-speed fiber based wireless access. We have been investigating signal-processing strategies to improve the performance of fiber based wireless access schemes cost-effectively.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Fiber-to-planar waveguide couplers find their applications in different kinds of optoelectronic devices such as polarizers [1], switchers [2], channel dropping filters [3], and others. The basic theoretical approach to investigate parameters of these devices is a coupling mode theory [4]. In this work we propose a simple method to calculate the coefficients of an excitation of all modes of the multimode composite structure by fiber mode at the junction: fiber - fiber with overlay waveguide. For the sake of simplicity fibers have been substituted by equivalent planar waveguides. Parameters of the equivalent waveguides can be chosen using a useful variational method [5]. The structure under consideration is shown in Fig. 1.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Recent advances in material science have sparked tremendous growth in the field of photonic crystals [1]. These novel optical materials consist of periodic arrays of dielectric material exhibiting strong Bragg-scattering of electromagnetic waves, which in certain cases leads to the formation of a photonic band gap (PBG). Under suitable circumstances with respect to material composition, topology and lattice symmetry, forbidden frequency ranges may be created over which ordinary propagation of electromagnetic radiation is absent irrespective of the direction of propagation, while, at the same time, the material is non-absorbing. The ability to tailor electromagnetic dispersion relations and the associated photonic mode structures through suitably engineered photonic crystals facilitates a new approach to applications such as low threshold, high efficiency micro-lasers, high modulation speed laser systems, ultrafast all-optical switches, all-optical micro-transistor and the integration of such devices onto an optical micro-chip.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Wavelength dilation is a technique sometimes used in optical switching systems wherein the number of wavelengths available inside the switching fabric is larger than the number of wavelengths transported on the inputs to the switch. This is similar to time dilation in TDM switches where the speed of the fabric is higher than the speed of the input ports. The aim of both types of switch dilation is to reduce contention inside the switching fabric.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The role of active Arrayed-Waveguide Grating (AWG) in future dynamic Wavelength Division Multiplexing (WDM) networking and routing was investigated. Simulations were done using the Beam Propagation Method (BPM). The results of this study indicate that active AWG can be used in multiple channel control with SNR up to 19 dB and dynamic dispersion compensation of up to 160 ps/nm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In a wavelength-routed WDM network, a lightpath must be established between a pair of source and destination nodes before data can be transferred. Due to the limitation in the number of wavelengths on each fiber link, efficient use of the wavelength resources is crucial for achieving good network performance, especially in the absence of wavelength conversion. While a good routing and wavelength assignment (RWA) algorithm [1] is critically important in improving the network performance, wavelength rerouting offers another effective way that can also increase the wavelength utilization and thereby improve the network performance in terms of the connection blocking probability.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The direct write laser-machining process is based on CNC technology and therefore it is assumed that the laser beam focal spot scans the workpiece surface in conformance with the predetermined tool path. However, laser- machining experiments indicate that the geometric quality of the machined part is not only defined by the pre- determined tool path but is also largely influenced by the dynamics of the laser-material interactions. The geometry and surface profile of the machined part is the result of a combined effect of the complex dynamic processes accompanying the machining process. All laser-machining systems have unique dynamic characteristics, represented by random variations of process parameters, e.g., pulse energy, travel speed, etc. Thus, accurate prediction of part quality becomes very difficult, requiring a systematic experimental study for each specific material and the laser-machining system. The objective of this work is to experimentally investigate the effect of variations in laser pulse energy on the geometric quality of the machined parts in terms of accuracy, precision, and surface quality.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Plastic optics are often mass produced by injection, compression or injection-compression molding. Optical quality molds can be directly machined in appropriate materials (tool steels, electroless nickel layers, aluminum, etc.), but much greater cost efficiency can be achieved with electroformed mold inserts. Traditionally, electroforming of optical quality mold inserts has been carried out in nickel, a material much softer than tool steels which, when hardened to 45-50 Ilk usually exhibit high wear resistance and long service life (hundreds of thousands of impressions per mold). Despite their low hardness (<20 HR,), nickel molds are successfully used to injection or compression mold Fresnel lenses, retroreflective sheeting, conventional spheric and aspheric lenses, various diffractive surfaces, compact discs and other products. However, electroformed nickel inserts usually allow to mold only tens of thousands of impressions before they are scrapped due to wear or accidental damage. This drawback prevented their wider usage in general plastic and optical mold making.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We present our latest work in the laser micromachining of silicon. A kilohertz-repetition-rate diode-pumped Nd:YLF laser (in infrared, green or ultraviolet modes) is focused on the surface of silicon wafers in a chlorine atmosphere for an enhanced magnitude and control of the etching rate. In particular, the use of an infrared laser beam is singled out, along with the advantages that it holds.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Low energy ion implantation induced quantum well intermixing is an attractive way to obtain bandgap tuning across laser heterostructures. This technique is well suited for InP based heterostructures where the amount of blueshift obtained is closely linked to the amount of point defects created through ion implantation. We have developed novel masking techniques for the fabrication of multiple bandgap heterostructures using a single ion implantation step through variable thickness masks. Two main approaches have been studied for ion implantation masking in order to address both high precision and large flexibility of the mask thickness.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Lasers are used for a variety of micro-machining applications because these tools provide a highly focused energy source that can be easily transmitted and manipulated to create geometric micro-features, often as small as the laser wavelength. Micro-machining with a laser beam is, however, a complex dynamic process with numerous nonlinear and stochastic parameters [1-3]. At present, the operator must use trial-and-error methods to set the process control parameters related to the laser beam, motion system, and work piece material. Furthermore, dynamic characteristics of the process that cannot be controlled by the operator such as power density fluctuations, intensity distribution within the laser beam, and thermal effects can greatly influence the machining process and the quality of part geometry.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Investigations are being carried out to improve the quality of laser micromachining of glass and semiconductor materials and to achieve submicron finished tolerances. Experiments have been carried out mainly with wavelengths ranging from 248 to 800 nm and pulse lengths of 130 to 400 fs. Comparisons are also being made with machining using 10 ns excimer laser pulses. Laser ablation thresholds, incubation coefficients and ablation rates are measured using single and multiple shot irradiation over a range of incident fluences with well controlled gaussian beams. New techniques for debris removal and crack minimization are being investigated. One technique for debris removal uses a sacrificial thin film of sputtered tungsten on top of the substrate before micromachining. After ablation, the tungsten film and deposited debris may be etched away with hydrogen peroxide. This technique has shown promising results in leaving a much cleaner surface. In order to reduce the amount of cracking of the substrate during laser drilling of glass, we have also been investigating the use of preheated substrates. By raising the temperature of glass before drilling, the sample is more ductile and less prone to cracking.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Many research groups both in academia and in industry are currently developing innovative nanoscale devices which could have a tremendous impact in the general areas of photonics and electronics. However techniques for fabricating these devices and nanostructures must be available in the form of production tools in order to find real applications. There are currently two major approaches under study as fabrication methods for nanodevices: these are microfabrication based techniques and molecular assembly techniques. The microfabrication approach, which is to be discussed here, is strongly based on the technology developed over the past decades for the fabrication of electronic devices and integrated circuits. The continued miniaturisation of these devices has far surpassed expectations for a technology developed initially for micrometer sized structures, and this approach now encompasses the fabrication of devices with dimensions well below 100 nm, even in production environments. There are also methods under study which do not yet meet industry standards in terms of, for example, throughput and repeatability, but which have shown significant promise. These include new techniques such as nano-imprint lithography, as well as established research tools such as electron beam lithography, which are becoming more and more relevant as equipment manufacturers such as Canon are now developing new types of production level tools.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Microfabrication for integrated MEMS is the art of combining micro electronic circuits with micro optics, mechanics, fluidics, sensing and other technologies. To meet the diversified requirements for MEMS (Micro Electro Mechanical Systems) and MOEMS (Micro Opto Electro Mechanical Systems), a broad spectrum of materials and fabrication processes must be available. INO is the only entity offering MEMS foundry-type services in Canada. These services include design, prototyping, fabrication of mini-series, packaging and testing of various MEMS.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A novel laser tunning technique, fully compatible with conventional CMOS processes, is described for analog and mixed microelectronics applications. In this method, a laser beam is used to create a resistive device by melting a silicon area, thereby forming an electrical link between two adjacent p-n junction diodes. These laser diffusible resistances can be made in the range of 100S2 to a few MS2, with an accuracy of 5Oppm, by using an iterative process.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Conventional mechanical machining can produce workpieces and assemblies with typical feature sizes larger than a few hundred microns. However, the steadily increasing demand for smaller sizes requires new tools and processes. Laser micromachining is a technique that offers precise, non-contact and accurate machining of very small components, and is an emerging advanced manufacturing technology that is being adapted to widely diverse industrial applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
An intense femtosecond laser focussed inside a transparent dielectric material changes the refractive index of the material. Buried waveguides were written by scanning the focal spot along the sample. The waveguide losses are -1dB/cm and the change in refractive index is 5x10-3 for a scanning speed of 200µm/s. To determine the conditions for high quality waveguides we characterized them by varying laser fluence and the scanning speed. The infrared photosensitivity can be used to write three-dimensional photonics structures.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Nanostructured silicon can exhibit visible photoluminescence (PL) with quantum efficiency of up to few percent, although bulk silicon has a small (1.11 eV) and indirect band gap. This luminescent property gives a promise fo the creation of Si-based optoelectronics devices and their potential integration in standard Si-based microelectronics chips. The search of methods for the production of visible light-emission from Si-based materials becomes currently a great task and a subject of numerous studies, while "dry" fabrication techniques are of particular interest due to a much better compatibility with silicon processing technology.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper will discuss the application of laser technology to two areas that require mass production techniques in the manufacture of printed circuit or printed wiring boards (PCB/PWB). These result from the increasing degree to which the packing densities of components and tracks is required to increase keep pace with the rapid expansion of the input/output (1/0) functionality that is placed upon individual boards.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The photonics industry has developed specialized process technology to fabricate optoelectronic devices in InP based material systems. We define features narrower than 100-nm to fabricate gratings in distributed- feedback lasers. There are waveguides many tens of microns across with dimensional tolerances near ± 0.1 ,um. We often require several stages of epitaxial processing, typically metal organic chemical vapour deposition (MOCVD) with micro-fabrication steps in between. Preparation of interfaces is often crucial, particularly prior to MOCVD and diffusion processes. We often deposit thin films on etched or cleaved facets to provide passivation or to adjust reflectivity. The films must endure harsh aging at high temperature under intense illumination. These and many other processes were developed during the pioneer days on wafer pieces using equipment that lagged far behind the sophistication of the Silicon industry. More than a decade ago Nortel Networks was among the first companies to transfer the processes to a 2- inch wafer standard. Nortel Networks has recently made a substantial capital investment to put our InP processes on 3-inch wafers with more modern equipment to further improve process control, cycle time, and yield. This presentation is a quick survey of some of the successes and challenges we encountered.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
For those with total hearing loss, there are no direct remedies except for electronic (i.e. cochlear) implants. They are invasive and do not always function in a satisfactory manner. Although sign language opens the window to a rich culture but communication with the hearing world is hindered. Lip reading can bridge that gap but communication is not without some stress. Inability to detect possible life threatening situations outside the visual field also affects the quality of life for those without the ability to hear. If the hearing process is viewed from the point of system engineering, there is a sound source and air is the transmission medium to the ear. The hearing structure of the ear converts mechanical vibrations to electrical signals that are then transmitted through nerve paths to the section of the brain where sound signals are processed. In most cases of total hearing loss, the hearing structure of the ear is non-functional. A cochlear implant bypasses this hearing structure. It electronically converts sounds from the air into their frequency components and feeds them into transmission nerve paths to the brain as electrical signals. This system-engineering point of view suggests that other pathways to the brain might be explored. The following section considers the visual pathway.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Accurate photodynamic therapy (PDT) treatment planning and monitoring requires quantitative knowledge of the in vivo tissue photosensitizer concentration 1'2. We introduce two new, non-invasive and rapid methods of performing this task. The advantages of both techniques are that they require only simple point measurements and are model-independent.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Chlorinated hydrocarbons (CHCs) are among the most frequently detected volatile organic compounds in North American ground-water supplies. They have been widely used in the chemical industry as solvents and degreasing agents. The average concentration level for CHCs in our aquatic environment ranges from high-ppb for chloroform to low-ppb level for tetrachloroethylene(PCE). Methods used for detecting these compounds in the environment require high sensitivity and high selectivity. Conventional detection methods for CHCs include gas chromatography(GC) or GC/MS. Although these techniques do possess the required sensitivity and selectivity, they lack the capability of performing in-situ measurements.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The performance of a plastic medical device depends not only on its bulk material properties, but also on the surface characteristics of the material. However, the suitability of the surface properties is often compromised in favour of the bulk properties, or due to economic considerations. In light of the fact that surface properties govern biological interactions with devices, there is an increasing emphasis on treating the surface to improve their performance in-vivo. Modification techniques that are employed involve modifications of the surface chemistry and/or morphology and include corona discharge, plasma deposition, ion beam irradiation, the immobilisation of biologically active molecules/ligands and photolithography. In general, these treatments proceed without affecting the bulk properties.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photodynamic therapy (PDT) a new cancer treatment modality involves optical irradiation of photosensitized biological tissue. The activation of a photosensitizer is determined by the product of the absorption coefficient of the photosensitizer in the tissue and the light energy dose. Furthermore molecular oxygen is an essential part of the therapy. Hence the safety and efficacy of PDT depends on the accurate knowledge of the fluence light dose throughout the target tissue, knowledge of the photosensitizer concentration and partial oxygen pressure (p02).1-2
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The standard method of performing investigations in cell biology consists of studying the behavior of average populations to extract information of the events occurring at a cellular and molecular level. Despite the unquestionable amount of knowledge accumulated with this approach, a closer look at the behavior in a single-cell and even subcellular scale is becoming more desirable as a way to study rare event populations. This becomes possible with the advent of an increasing number of fluorescent probes, which are compatible with cell viability and permit the monitoring of the morphological and physiological changes of a single cell following a particular challenge. The number of observed events can be kept large to ensure adequate population statistics. Changes associated with morphological and physiological responses are encoded with fluorescence parameters such as intensity, wavelength and spatial localization variations and fluorescence lifetime. In addition to this, following a particular challenge, confocal microscopy is a powerful tool to track these changes over time. It also provides a method of following the behavior of a large number of cells even at high magnifications, due to its versatility and automatization capabilities.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Laser induced ablation is widely used for the removal of tissue. The advantage is seen in minimising the stress on the remaining tissue. However the picture that all irradiated light energy is converted into energy for the phase transition from solid to vapour is too simple. The crater bottom and the side walls are heated, and it is a question of relaxation time, heat conductivity and heat capacity which determines the degree of thermal damage. Furthermore the optical penetration depth, the pulse duration and the repetition rate determine the thickness of the thermal influenced zone. This presentation reports on the influence of the repetition rate of CO2 laser radiation with a pulse length oft = 80 'is on the efficiency of ablation and the thickness of the thermal damage.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Experimental Details-Global Set-up Human tumour cells were embedded in the chorioallantois membrane (CAM) of hen's eggs. As a light source we used a Xenon arc lamp with colour filters, a He-Ne laser, and a self-built flash lamp pumped dye laser. The fluorescence induced by the light source is monitored via a microscope (Zeiss Axiotech) followed by a CCD camera or a "SpectraCube" spectrometer.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Model Calculations The tissue was modelled by the so called Krogh's cylinders, i.e. blood parallel vessels in a specific distance supply the tissue with oxygen. Oxygen transfer in the tissue takes place due to diffusion only which needs an decrease of oxygen concentration with increasing distance to the vessel. A oxygen diffusion rate of D = 2 10-5 cm /s was used. The rate equations for the population density in the levels of the photosensitizer molecule and in the oxygen molecule were build up. All transition shown in Fig. 1 have been considered with the marked rate constants. The system of coupled differential equations were solved numerically on a personal computer which needed computing time up to 36 hours.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The ability to analyze a large field of parameters (<<100) from a fairly large population of cells (1000) on a cell-by-cell basis quickly and accurately, presents a major challenge for the fields of both cellular biology and analytical biochemistry. This ability, however, would give the researcher the means to identify and study variations within a given populations. This knowledge of sub-populations has profound implications in fields such as cancer biology', and cell differentiation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Myopia is very prevalent and almost epidemic in some countries. The enormous amount of research in this topic is indicative of the complexity of factors influencing myopia and the problems produced by myopia (see Goss and Wickham 1995, Wallman 1993 for a review of this topic and Edwards 1996 for a review of the animal studies). In particular, research is trying to determine the mechanisms that trigger the development of myopia and why some groups of individuals experience a severe myopic decline. There is evidence of a genetic component to myopia but environmental factors (such as near work) are less well understood. Wallman (1993) suggests that it is a combination of both factors. This study presents the hypothesis that there is a genetic predisposition to myopia, which may then be triggered by environmental conditions.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Clinical Magnetic Resonance (MR) imaging relies on the protons of hydrogen atoms (in water molecules) in tissue to provide the signal. Certain organs, for example the lung have been difficult to image because of low signal due to low density and heterogeneity of the tissue that induces susceptibility effects. 129Xe gas (xenon) can help MR imaging of the lungs since the nuclear-spin polarization of the xenon atoms can be increased by laser optical pumping and spin exchange. This process produces hyperpolarized xenon (H-Xe), in which the signal is enhanced by up to a factor of about 104(1).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photodynamic therapy (PDT) has proven itself worthy of continued research as a viable treatment of certain neoplastic growths (1). The past decade has seen a deluge of research papers describing the use of PDT for a wide array of cellular and animal models. More recent studies indicate an increasing emphasis towards understanding the mechanisms of PDT and the various parameters that govern and predict its overall efficacy. Many questions remain to be answered with regards to the amount of drug and light that should be administered in order to ensure optimal photophysical activation of the photosensitizer. The ideal photodynamic treatment would achieve complete and selective ablation of the tumour following minimal drug and light. This has yet to be reported. Being able to extrapolate the mechanistics of light entering and activating the photosensitizer at the tissue level down to the subcellular level is no small task and will depend on the type of tissue and cells being targeted (2). Our studies focus on the subcellular effects of PDT, in particular the role of calcium and the events that lead up to PDT-mediated induction of apoptosis.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The long-term objectives of this research are to focus on the development of nanobiosensor devices based on bacteriorhodopsin (bR)suitable for applications in the areas of environmental monitoring and testing. Such biosensors may be interfaced directly to mobile, autonomous or semi autonomous robotic devices or be applied as part of integrated "bio-chips" for field analysis applications. The specific and immediate goals of this research are to investigate the application of bR as an optical transducer and also investigate specific applications such as biosensors for toxicity monitoring based on bio-luminescent systems coupled to bateriorhodopsin which is used as the biological signal transducer. A biosensor is defined as a compact analytical device incorporating a biological or biologically-derived sensing element either integrated within or intimately associated with a physico-chemical transducer. The usual aim of a biosensor is to produce either discrete or continuous electronic signals which are proportional to a single analyte or a related group of analytes [1]. The biological sensing element can be an enzyme, antibody,nucleic acid, antibody fragment, or a whole microbial cell, or plant or animal tissue.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Breast cancer is the most commonly occurring cancer in women and the lifetime risk (at age 85) of being diagnosed is approximately 1 in 10 [1], the highest probability out of all cancers. Breast cancer screening programs have been shown to decrease the mortality rates of women age 50-69 [2] due to detecting cancer at an earlier, treatable stage, however compliance is low due to a variety of reasons. While the understanding of the underlying causes and mechanisms leading to breast cancer is increasing, development of the disease is not fully understood. Hence, there has been a push to propose, develop and understand risk factors for the disease; which are defined as those characteristics that people with the disease have in common [3].
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Recent advances in the performance of light emitting diodes (LED) that emit near 630 nm has allowed the opportunity to develop efficient red light sources for photodynamic therapy with protoporphyrin IX") (ALA-PDT). LED lamps similar to those described here have been reported along with their clinical effectiveness('`). Light sources for PDT can be characterized by their spectral irradiance, irradiance uniformity, depth of focus, light output stability, electrical to optical conversion efficiency, beam size, cost, simplicity, reliability, maintenance requirements and overall functional lifetime. LED lights, for skin illumination, may be superior to currently available incoherent lights. Several light sources, that have been used for ALA-PDT, were evaluated by Gudgin Dickson et al 3) using a scanning point measurement system.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The successful treatment of diseases (including cancer) by the use of drugs normally rely on a selective reactivity of a drug towards the unwanted tissue. An approach that is related to chemotherapy is that of photochemotherapy, normally called photodynamic therapy (PDT). In this treatment modality, a harmless drug (in the absence of light) is first introduced into the body and allowed to selectively biodistribute into the diseased tissue. Thus selectivity is no longer based on reactivity, but on the selective retention of the drug in abnormal tissue. Once selective biodistribution has taken place, the drug is photoexcited with light in the visible or near infrared range. Drugs that absorb near infrared light are desirable due to the increased tissue penetration at these wavelengths. PDT is a relatively "benign" treatment approach in which a normally harmless drug is combined with safe, non-ionizing light in order to initiate a photochemical reaction that leads to the selective killing of the diseased tissue. The reactive intermediate is believed to be singlet oxygen, generated by an energy-transfer (type II) process between the excited state of the drug (photosensitizer) and ground state oxygen. Singlet oxygen is a highly reactive oxidizing agent that will rapidly react with aromatic double bonds found in cell membranes. Resulting cell death can be either via apoptosis or necrosis, depending on the primary reaction site and the degree of damage.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
An automated beam profile analyzer has been developed to evaluate light beam profiles of both coherent and non- coherent light sources and to determine their suitability for use in photodynamic therapy (PDT) or photodiagnosis (PD), where both controlled and effective light delivery is crucial. It is the purpose of the system to characterize the output properties of the light source in terms of the stability, irradiance, and beam uniformity. The output light analysis system described is capable of quantitative analysis on a large variety of lamp sources for potential use in different photobiological applications, such as photosynthesis, environmental photobiology, and photomedicine, as well as many industrial applications. This system is described in detail in reference 1. Figure 1 is a pictorial description of the automated beam profile analyzer.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Certain types of fluorescent molecules can be exploited in medicine by virtue of the fact that they are retained for longer periods of time in abnormal tissue than in corresponding adjacent normal tissue. Such fluorophores can be used to noninvasively detect the presence, and the boundaries, of abnormal tissue, in a process called photodiagnosis (PD). Many such molecules can also act as photosensitizers, that when excited by light, can cause selective killing to abnormal tissue within which they are located (photodynamic therapy, or PDT). Various devices suitable for application in PD have already been developed, but these devices are expensive, maintenance-intensive, and require extensive user training. The absence of an inexpensive, routine PD device suitable for use in a wide range of applications in the clinics and in doctor's offices is one of the obstacles to wider acceptance of PD and PDT as a routine clinical tool.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photodynamic therapy (PDT) is a relatively new methodology currently being investigated for use in the treatment of cancerous or abnormal tissue. The principle of PDT relies on a photosensitizer that is administered to the patient, then photoexcited to induce a cytotoxic reaction. To be a useful drug for PDT, a photosensitizer should show specific properties. These include a preferential accumulation in abnormal tissue compared to normal tissue, a fast clearance time, a strong absorption in the red or near infrared region of the electromagnetic spectrum, and finally a toxicity in the presence of light but harmless otherwise.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Spatial and temporal distribution patterns of photosensitizers or their photoproducts is an important observation when attempting to understand the cellular and molecular effects of a particular photochemotherapeutic compound on cells and tissues. While fluorescence microscopy can be readily used to determine the spatial distribution of specific fluorophores within cells, certain limitations arise with this commonly used technique. These limitations include spectral overlap between probes and the fluorophore of interest, endogenous autofluorescence of various intracellular components, and artifactual signals derived from exogenous dyes, all of which interfere with the fluorescent signals emitted from the molecules of interest in a study. The most significant artifactual fluorescent signals given off by intracellular molecules include fluorescence emitted from certain aromatic amino acids, collagen, elastin, pyridoxine, nicotinamide adenine dinucleotides, flavins, and several different porphyrins. In addition to these obstacles, the intercellular environment may influence some fluorophores when macroscopic analysis of tissues is performed. Different fluorophores have different photodynamic activities, photobleaching characteristics, emission wavelength maxima and bandwidths, and fluorescence quantum yields, all of which may lead to a shift in a particular emission signal by a certain fluorophore in a given tissue environment.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Light activated drugs are part of a new arsenal that has been actively pursued in the past decades against different types of diseases. When activated by non-ionizing radiation (visible light), harmless drugs can be quickly turned into very potent chemicals that can lead to the killing of cells, either via necrosis or apoptosis. Rather than depending on the selective reactivity between such drugs and the diseased cells/tissues, the search for light activated drugs has been mainly focussed on drugs that will selectively biodistribute towards the diseased cells or tissues prior to being activated by light. The selectivity would thus be determined not by the chemical reactivity of the drug towards different types of cells or tissue as is the case of many anti-tumour drugs, but rather by the process of selective retention of the drug in the unwanted tissue prior to its activation by light. Such a process could considerably reduce the damaging effects on normal tissue that often accompanies chemo- or radiation therapy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The study of pathogenic processes is mostly limited to in vitro assays, cell-culture techniques and post mortem examination of infected animals. A better understanding of the infectious process, efficiency of antimicrobial and antibiotic treatment as well as immunomodulatory effects of different food supplements could be achieved by in vivo real-time monitoring of bacterial colonization in live animals. It was proposed recently to use bacterial pathogens with luminescent or fluorescent phenotypes for photonic detection of bacterial cells in living hosts. 14 It was shown that both bacteria transformed with full cassette of luminescent genes from Xenorhabdus luminescens and with Green Fluorescent Protein (GFP) could be visualized in animal using whole-body luminescent or fluorescent imaging techniques with high sensitivity and in real time. We used this approach to investigate the effect of diet on the time-course of infection in mice orally infected with bioluminescent strain of Salmonella enteritidis.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Intrinsic fluorescence (IF) spectra, computed from measured fluorescence emission and diffuse reflectance (DR) spectra, are free from distortions by scattering and absorption. Using an original instrument called FastEEM, white light DR and fluorescence emission spectra generated at 11 excitation wavelengths were collected from heart transplant and autopsy cases. IF spectra were extracted by combining DR and fluorescence spectra using a photon migration model. IF spectra were fit to a linear combination of collagen and elastin spectra at 342 nm excitation, and collagen and component C at 480 nm. C spectrum was derived from multivariate curve resolution analysis and related to ceroid. We calculated contributions of collagen and elastin to IF at 342 and of C at 480 nm, and contribution of beta-carotene absorption to DR. A diagnostic algorithm was derived. Specificity, sensitivity, and validity were verified by leave-one out cross-validation. 110 coronary segments were studied: 22 normal and intimal fibroplasia and 88 atherosclerotic/atheromatous plaques. An algorithm using collagen contribution to IF at 342 nm, contribution of C to IF at 480 nm and that of beta-carotene to DR had sensitivity 95%, specificity 91% and PPV 98%. Fundamental parameters extracted from IF and DR spectra can accurately diagnose atherosclerotic lesions.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Light microscopy is a widely used tool in biomedical research. Fluorescence microscopy concentrates on quantitative and qualitative measurements of the fluorescent light emitted from the specimen under study. This is generally done using fluorescent molecules that can be tagged to antibodies, giving specific information about the micro-environment of the sample, i.e. oxygen concentration (tissue hypoxia), and/or to visualize specific structures, such as, tissue morphology (H & E), and blood vessel location (CD31). Biological applications of fluorescence microscopy such as imaging cut and stained tissue/tumour sections use specimens that 'overfill' the field of view of standard microscope objectives. An average tumour in these studies is 5-10 mm wide, while microscope objectives range in their field of view from -1 mm down to a few hundred microns, with smaller fields as magnification power increases. This can pose some difficulties for studies that look at the expression of a parameter across the entire specimen.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
It has been known since the 1960's that certain cellular dyes could inactivate live cells when illuminated but the research involving these compounds has focussed largely on the use of photodynamic therapy for mammalian carcinoma cells. Antimicrobial photodynamic therapy (APDT) research has increased in the last 20 years due to concerns with emerging antibiotic resistant bacteria, but is still in its early stages of development (Zeina et al., 2001).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A promising development in photodynamic therapy (PDT) is the use of two-photon excitation (TPE). The confinement of the excitation volume leads to the possibility of subcellular PDT. Thus, in order to design a treatment protocol, one must be aware of where a photosensitizer localizes in a cell and the individual differences, both between cellular localization sites and individual cells. One way to determine the subcellular location is to observe photobleaching dynamics in cells and compare the rate constants to those observed in solvents which have been chosen to model different characteristics of environments, such as polarity. We have observed the photobleaching behaviour of Verteporfm (VP) in a variety of solvents and single cells and have been able to correlate subcellular position with environmental polarity.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Periodontal disease is a family of chronic inflammatory conditions caused by bacterial infections.' It is manifested in red, swollen gingiva (gums) and can lead to destruction of the connective tissue and bone that hold teeth in place. Conventional treatments typically require some form of invasive surgery, depending on the disease stage at time of detection. Photodynamic Therapy (PDT) is the use of light-activated drugs (photosensitizers) for treatment of a variety of conditions 2 such as solid tumors, pre-malignancies, macular degeneration and actinic keratitis. There have been a number of studies of PDT as an antibacterial agent. 3'4 Depending on the photosensitizer and strain of bacteria, significant killing (several LOGS) can be achieved.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Surface Plasmon Resonance (SPR) has been considered as a leading instrumentation for direct, label-free detection of recognition and binding events between a target analyte (antigens, hormones, DNAs, etc.) and its corresponding receptor (antibodies, capture probe DNA, proteins etc.) immobilized to the surface/liquid interface. Conventional SPR systems are based on a glass technology, in which p-polarized light, is directed through a glass prism and reflected from a gold film deposited on the prism surface. SPR effect causes a dip in angular (wavelength) dependence of the reflected light intensity with the resulting position extremely sensitive to the refractive index and the thickness of the thin biolayer. This remarkable property has been employed towards the development of SPR- based biosensors1'2, for real-time characterization of biological interactions on the gold surface (for review, see, e.g. Ref. 3).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Canadian Light Source is one of the largest scientific projects in Canada, and one of the most advanced synchrotrons in the world. This new research tool at the University of Saskatchewan will help to find Canadian solutions for global challenges in health, advanced materials and the environment. Biological applications will play an important role in SR research programs, in fact, among six beamlines scheduled for operation in year 2004, such as: • IR beamlines: o far IR high resolution spectroscopy for gas phase and surface science (20cm-1-2000cm-1). o mid IR spectromicroscopy (500cm-1 -12,000cm-1) for biological and industrial applications. • high resolution (>104) Variable Line Spacing Plane Grating Monochromator; 8-250eV for angular resolved PhotoElectron Spectroscopy. • Spherical Grating Monochromator beamline from the SRC, Wisconsin; 200-1900eV for general type spectroscopy. • Spectromicroscopy beamline, designed for 100-2000eV energy range and full polarization control of SR radiation. • protein crystallography beamline, operational in 6-18keV energy range. • general purpose µXAFS, which focus hard x-ray beam (3.5-40keV) to a spot as small as 10 micron in diameter,
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Purpose: Conventional endoscopic imaging in human colon detects large hyperplastic and adenomatous polyps (<5mm diam). However, detecting smaller early neoplastic lesions and flat adenomas is problematic. To improve the detection of such lesions we assessed the utility of fluorescence contrast agents for enhancing contrast between normal and abnormal tissues. To this end, a near infrared (NIR) fluorescent dye conjugated to a monoclonal antibody (MAb) with high affinity for a tumour-associated-glycoprotein (TAG72) antigen commonly found in colon tumours was studied as a potential fluorescence contrast agent.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photodynamic therapy (PDT) is an innovative and attractive modality, which is potentially beneficial for the treatment of a number of cancers either as stand-alone or as adjuvant treatment. Currently PDT is in a Phase III clinical trial for the treatment of intracanial neoplasms using Photofrin as the Photosensitizer (Muller et al). Selectivity of PDT treatment is based on the inherent selectivity of the photosensitizer towards malignant cells and light fluence distribution within the tissue of a monochromatic source that matches the absorption spectrum of the sensitizer. However, there is currently, no individualized dosimetry or monitoring system for treatment progress using either a direct or indirect biological responses, available, which would enable the physician to modify the treatment or repeat it while photosensitizer in under treated tissue is still available.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Ultrafast `pulsetrain-burst' machining has proven to deliver qualitative advantages for the processing of hard materials. This approach to tailoring the delivery of radiant exposure uses microsecond bursts of picosecond or femtosecond pulses. The mixed-timescale mode reaps the rewards of providing laser-material interactions at ultrashort timescales, while allowing for some control of heat and stress dissipation over longer timescales. As a result, our group has been able to ablate hard materials such as aluminum [1], as well as optically transparent materials like fused silica [2,3] beyond the capabilities of more conventional methods that employ slower repetition rates. It is well known that gross differences in the end results of materials-processing are the result of the manner in which the laser fluence is delivered - wavelength, continuous-wave vs. pulsed, pulse shape, and the pulse duration itself all have significant impact, and each parameter-value has significant advantages. For brittle materials, where limited tolerance to heat and tensile stress sets limits on the etch-depth possible for multi-kHz repetition rates, 'pulsetrain-burst' machining has enabled us to drill deeper and more cleanly, while eliminating damage due to thermal cycling and over-pressure shocks.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Fluorescence Photobleaching Recovery (FPR) has proven to be a versatile technique for assessing the transport phenomena of fluorescently tagged proteins. Effective diffusion coefficients are estimated by observing the rate of fluorescence recovery resulting from the influx of fluorophores into a volume rendered non-fluorescent by photobleaching. Diffusion coefficients may be determined through non-linear regression of a theoretical model' or by relating half times of recovery to calibration data2. Due to the lack of axial confinement inherent in confocal FPR, analyses are limited to two-dimensional systems. However, with the development of multiphoton microscopy, three-dimensional diffusion coefficients can now be determined with a spatial resolution of a few microns3.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photodynamic therapy (PDT) of cancer is a treatment with strengths and weaknesses. Amongst the latter is the need for the presence of oxygen for the photodynamic effect to occur. It is a known fact that singlet oxygen, generated from the first triplet excited state (T1) of the photosensitizer, is responsible for the lethal photodynamic effect [1, 2, 3, 4]. The problem lies in the lack of oxygen in the core of a tumor. It seems that the excited triplet state energy of the photosensitizers currently in use in PDT lies below the threshold of a lethal anoxic chemical reaction.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A variety of imaging techniques have been developed in order to optically detect foreign inclusions, inhomogeneities or defects in opaque and/or scattering materials. This issue is of particular importance in the biomedical field where imaging through biological tissue finds immediate applications especially tumor detection inside the human body.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Low intensity laser therapy (LILT) is currently undergoing investigation as a treatment for chronic wounds. Although the intended target is the wound bed and surrounding skin, wound bacteria are also exposed and hence subject to LILT, thus a good understanding of the effects of LILT on bacterial growth is essential for prescribing safe and effective laser therapy for wounds. The present work examines the effects of 810 nm laser on bacterial growth. The objectives were: 1. to determine an effective combination of radiation parameters leading to bacterial inhibition, or alternatively 2. to determine which combination of laser parameters produce the least stimulation of bacterial growth.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
As one of the most relied upon senses, an understanding of the visual system is essential. There are two focussing lenses, the cornea and the crystalline lens, contributing approximately 40D and 20D, respectively, to the total power of the eye. The anterior surface of the cornea is shaped like a prolate ellipsoid (Kiely et al, 1982).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The cornea and the crystalline lens form the image on the retina of the human eye. Tilt and decentration of the components and the angle of the fovea (area of most acute vision) from the optical axis also contribute. The resulting image quality on the retina is influenced by diffraction through the circular pupil of the eye, by the scattering of light, by chromatic aberration and by the monochromatic aberrations of the system. In this presentation, we will concentrate on the monochromatic wavefront aberrations of the eye, their measurement, and their influence on vision and ophthalmic diagnosis.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This work reports a physical model that relates charge transport to the exciton formation rate in organic electroluminescent device. The model assumes ideal charge density profiles and the existence of an "optimal" charge separation for excitons to be formed. This allows the exciton formation rate to be dependent on the charge density profiles as well as parameters linked to the exciton formation process. Field dependent effect enters into this model through a "localization" parameter, which is related to the carrier mobility. When the model is applied to the ITO/CuPc/NPB/A1q3/Mg system, we have found it possible to address a number of observations not fully explained previously.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In electrical impedance tomography (EIT), different currents are applied to electrodes on the surface of an object and the resulting voltages are measured. The image of impedance (resitivity, conductivity) distribution or changes in the object is reconstructed based on these boundary measurements. EIT is a functional imaging technique, which may reveal the physiological and pathological information by human body's impedance properties. The advantages such as the non-invasive modality and the relative low cost make EIT become a research hot in medical imaging. However, the image reconstruction in EIT is a high ill-posed, non-linear, inverse problem, and it becomes a key and difficult point in EIT. In dynamic EIT, the image of impedance changes in the object is reconstructed. On the other hand, the image of impedance distribution in the object is reconstructed in static EIT, which is more difficult than in dynamic EIT. We study the reconstruction of static EIT in this paper, due to the static EIT has better clinical application prospect than the dynamic EIT.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
SUMMARY In this work we analyze optical distortion for three types of missiles using three different turbulent models, with different degree of complexity, for the density fluctuations and show the effect that turbulent flow has on the performance of optical systems, like MTF and Strehl Ratio.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper discusses the geometrical relationship between a two dimensional grid of lines and an illuminated screen pixelation and the Non-Moire spatial interference pattern that arise from their interaction. In our case we have a two dimensional pixelation of illumination at the screen. We have a two dimensional EMI (Electro Magnetic Interference) mesh grid (horizontal and vertical wires (thickness = 0.0012 inches) at 90 degrees to each other with 50 openings per inch (opi),80 opi and 100 opi); this mesh can be oriented at some angle of the horizontal wires of the mesh to the pixelation of the screen. This creates a spatial interference pattern which is different from that of a traditional Moire pattern.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Organic Light Emitting Diode displays attain higher performance when addressed by an active matrix. However, in conventional designs the OLEDs has to emit through the substrate and the active matrix which must be fabricated before the OLED is deposited. Because OLEDs require a high current density, the addressing elements take up the majority of the space in the pixel, resulting in a low aperture ratio. We have developed fabrication processes for top- emitting OLEDs that solves the problem and provide more flexibility in the design of the matrix. The top transparent electrode is ITO sputtered at room-temperature and low power to minimize damage on the underlying organic layers.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
To extend the depth-of-focus of incoherent imaging systems an aspherical pupil plane element is designed to encode the incident wavefront in such a way that the image recorded by the detector can be accurately restored over a large range of defocus. This approach alleviates thermal and chromatic defocus whilst maintaining diffraction-limited resolution for incoherent imaging systems [1] by using simple and low-cost one- or two-element lenses. However this is bought at the price of a reduction in signal-to-noise ratio of the displayed image as is associated with most inverse filtering problems. This sets a serious limit to future applications, particularly in thermal imaging where the optical systems involve fast optics with a very small depth of field for which signal-to-noise ratio of restored images can be reduced significantly.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Because of the constant increasing demands of images exchange, and despite the ever increasing bandwidth of the networks, compression and multiplexing of images is becoming inseparable from their generation and display. For high resolution real time motion pictures, electronic performing of compression requires complex and time-consuming processing units. On the contrary, by its inherent bi-dimensional character, coherent optics is well fitted to perform such processes that are basically bi-dimensional data handling in the Fourier domain. Additionally, the main limiting factor that was the maximum frame rate is vanishing because of the recent improvement of spatial light modulator technology. The purpose of this communication is to benefit from recent optical correlation algorithms. The segmented filtering used to store multi-references in a given space bandwidth product optical filter can be applied to networks to compress and multiplex images in a given bandwidth channel.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Novel readout and support-circuit concepts in a CMOS imager are described for the replacement of conventional silicon photodiodes in applications requiring bandwidths of 1 MHz and more. Conventional silicon photodiodes are the detector of choice for high-speed applications but have been replaced by CCD arrays and CMOS imagers when spatial resolution is needed. These imagers can be comparable to photodiodes in responsivity and generally have the advantages of lower noise, low cost, compatibility with 'system-on-a-chip architectures and the ensuing low power and low cost. For space applications, the CMOS devices are highly tolerant of ionizing radiation. With a novel readout architecture and suitable digital and analog support circuitry on- chip, a CMOS imager concept has been identified to replace conventional photodiodes in some important niche applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
All medical x-ray imaging today is done using the transmitted photons, i.e., those x-ray quanta which do not suffer any interaction within the patient. An alternative is to use the more plentiful scattered photons. Backscatter is almost entirely Compton (incoherent) scatter, which is principally sensitive to the number of electrons per unit volume. Forward scatter is dominated by coherent scatter, which is the basis of x-ray diffraction. Its cross section varies with angle and photon energy in a material-specific manner, even for amorphous materials. The dependence on Z and chemical structure allows it to be very useful in distinguishing tissues within the patient. Many workers have demonstrated utilization of both types of scatter in the lab, but it has been difficult to compare the performance of these systems with conventional transmission imaging. Therefore, we devised a semi-analytic model of scatter imaging. Our calculations predict that for some imaging tasks the contrast and signal-to-noise ratio achieved by collecting a portion of the scatter (in an annular cone) will be superior to that achieved by conventional transmission imaging, for the same number of photons incident on the patient. Our analysis is reliant on the limited published data for coherent scattering for biological materials.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The most widely used architecture in large area amorphous silicon (a-Si) flat panel imagers is a passive pixel sensor (PPS), which consists of a detector and a readout switch. While the PPS has the advantage of being compact and amenable towards high-resolution imaging, reading small PPS output signals requires external circuitry such as column charge amplifiers that produce additional noise and reduce the minimum readable sensor input signal. This work presents a current mode amorphous silicon active pixel that performs on-pixel amplification of noise-vulnerable sensor input signals to minimize the effect of external readout noise sources associated with "off-chip" charge amplifiers. Preliminary results [1] indicate excellent small signal linearity along with a high, and programmable, charge gain, which is promising for diagnostic medical imaging. This work examines low frequency a-Si TFT thermal and flicker noise, which contribute to the overall noise performance of the APS.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Electrical and Material properties of dielectric thin films of silicon oxynitride, deposited at low substrate temperatures using an ultrahigh vacuum electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD) system have been examined using X-Ray Photon Spectroscopy (XPS), Nuclear Reaction Analysis (NRA), Elastic Recoil Detection (ERD) and chemical etching. Electrical properties, capacitance and dielectric breakdown field strengths of these films are found to be comparable to films deposited in systems utilizing ion assist physical vapour deposition (PVD) and sputtering. Thin film electroluminescent devices incorporating ECR SiON dielectrics demonstrate high brightness and superior breakdown characteristics.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Microbolometer focal plane arrays can provide broadband visible to far infrared imaging and detection capability without a requirement for optical chopping or cryogenic cooling. Advancements in micro-bolometric technology are opening up new applications beyond the traditional long wave infrared thermal imaging used for night vision and thermography.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We report on the adaption of new particle physics gas proportional microdetectors filled with a xenon/methane gas mixture at high pressure as image receptors for medical x-ray imaging. Currently in radiology, all detectors used clinically merely integrate the energy deposited by the beam. The next generation of detectors for digital radiography and computed tomography (CT) will obtain extra information by counting individual photons and measuring their energy. This will enable (i) implementation of single exposure dual-energy radiography, (ii) for CT, reconstruction of images free of spectral artefacts, and (iii) for the same quantum efficiency, reduced image noise compared with images obtained by energy integration. The new gas microdetectors can measure individual photon energies at radiological fluence rates and have high spatial resolution. Prototype systems in our laboratory have demonstrated a limiting spatial resolution of 7.0 1p mm-' for a 30 kV x-ray spectrum and 11.9 1p mm-' for 50 kV. The energy resolution at 4 atm was 10% at 17.7 keV and 8% at 59.6 keV. The counting rate ability for unfiltered 30 kV x rays was < 2 x 106 mm-2 s-' at 3 atm of Xe:methane corresponding to an exposure rate < 25 mR s-1. Future systems in which the readout anodes are parallel to the photon direction will be capable of even higher rates.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
ECG-Gated SPECT is used widely to image myocardial perfusion and wall thickening which are important measures of heart function. An accurate model of the periodic count density variations is needed to estimate both the magnitude and precision of perfusion and wall thickening. We propose a new model of wall thickening which better suits the non-uniform (eccentric) changes in count density than the standard sinusoidal (SIN) model. The sinusoidal eccentric thickening (SET) model is P + W sin( t + 0 ) e(-5 (1-sm( t + 0 )) where P is perfusion, W is wall thickening, t is gate number [1-8], 0 is phase and 8 is the eccentric coefficient in the exponential term.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
With a spatial resolution of about 1 km at geostationary altitude and three spectral bands, visible, MR and SWIR, the CCD sensor of the Insat-2E satellite is the first of its kind used for meteorological applications. These CCD images contain up to 31 lines each composed of 7165 x 300-pixel high vertical frames. After launch, images were found to be contaminated with stray light from an unknown origin. As a result, there are strong false gradients between CCD lines and a deformation of the frame radiometric profiles depending on the general scene albedo. These artifacts adversely affect meteorological applications, in particular cloud motion wind vector determination and vegetation indexes. Because a full sensor technical description was unavailable, it was impossible to develop an analytical approach to assess possible causes. Instead, an empirical method was developed in order to reduce false gradients and excessive luminance. The proposed method had to be simple and fast for real time processing purposes.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This article reports techniques used for reduction of the dark current density of amorphous silicon (a-Si:H) p-i-n photodetectors under reverse bias to the 10-12 A/cm2 range. This range of dark currents is critical in applications involving low-level light detection. The dark current of these devices is significantly affected by the quality of the p-i interface and the band-gap of the p-type material. The latter can be addressed by employing of a p-type large band-gap (2.23eV) material such as amorphous silicon carbide (a-SiC:H) layer so as to increase the built-in potential at the junction. This should decrease the dark current, however, the transition from a-Si:H to the large band gap p-type a-SiC:H layer leads to a band-gap discontinuity, which can degrade the integrity of the interface. Thus, a graded layer is introduced at the p-i interface to provide a smooth transition of energies over a few monolayers. In addition, a thin insulating silicon carbide p-layer is introduced prior to deposition of the heavily doped p-region to further reduce the dark current.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Computer assisted interpretation programs are used widely for the initial diagnosis of coronary artery disease, but are not yet available to help monitor the progression of disease over time. We developed the direct paired comparison (DPC) method to assess the statistical significance of changes in serial positron tomography (PET) perfusion scans, which is now adapted for serial ECG-gated single photon tomography (SPECT). The purpose of this study was to evaluate the specificity and sensitivity of DPC for the detection of significant changes in perfusion and wall-thickening with gated SPECT. Scan data were simulated with uniform perfusion (100%), wall-thickening (20%), and Gaussian noise (20%). Gated count density curves were fit with an eccentric sinusoidal thickening model. Perfusion and wall-thickening differences between baseline and repeat data (n=500) were analyzed using DPC under the null hypothesis (Ho) to assess specificity. Measured 16-gate data (n=5) were then split into 8-gate pairs to verify specificity.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Cardiac PET images suffer from partial volume (PV) losses, a result of motion and limited resolution. A correction can be made using an extravascular (EV) density image, constructed via the subtraction of a blood volume (BV) image from a transmission image (TX, image of tissue density). The ability of the EV image to correct for PV losses is dependent on the noise in the TX image, and by errors in alignment between the TX and BV images. A TX image can be obtained in either a pre-injection or post-injection mode, depending on whether it is taken before or after injection of activity to the subject. The purpose of this study was to determine which TX image best minimizes errors in the EV image. A simple plastic cardiac phantom was used to compare the two TX modes. Calculation and comparison of the centers was used to determine the pre-injection misalignment. Pre-injection offset was -0.33±0.85 mm vertically, and -0.64±0.72 mm horizontally from the post- injection image. A CoV of 0.0231±0.004 and 0.0374±0.006 was measured for the pre and post-injection images respectively. These results indicate that the pre-injection TX has the best statistical quality, but provides poor alignment.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Interpretation of FDG PET images is complicated by partial volume (PV) averaging, a result of cardiac motion and limited scanner resolution. An extravascular (EV) density image, created from the subtraction of a blood pool scan from a transmission scan, can be used for correction of PV averaging. Computer simulations were performed to develop this method. The PSF of the scanner was measured and found to be gaussian with a FWHM of 9.7 mm. Images were subsequently created through convolution of a true activity distribution with the PSF. The simulations showed that the EV density image could perfectly correct for PV effects, and predicted a value of 0.67 g/cc for the EV image, later validated using a cardiac phantom (0.68 +/- 0.016 g/cc). Measurements on a plastic phantom with a constant myocardial thickness of 10 mm were performed to validate the proposed method. A 32% reduction in myocardial activity was found before correction, significantly less than the true value (p<0.001). Application of the EV density image yielded the true myocardial activity (p=ns) after an artifact inherent to phantom studies was accounted for. These results indicate that PV averaging within the myocardium can be accurately corrected using an EV density image.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Amorphous silicon base d thin film transistors can be used to produce low cost, high quality, reliable active matrix OLED (AMOLED) displays. These displays can also be made on flexible plastic because the fabrication process does not need high temperatures. However, this material has the drawbacks of low electron mobility and defect metastability, which are a major hurdle in AMOLED applications. This paper presents and discusses pixel architectures and driver circuits that can overcome these drawbacks and make a -Si:H based active matrix OLED displays more efficient and reliable.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
One common approach with digital X-ray imaging using amorphous silicon is to integrate a uniform phosphor layer for conversion of X-ray to visible photons onto an array of image sensor pixels. Each pixel in the array consists of an a-Si:H photodiode (PD) and an a-Si:H thin film transistor (TFT) [1] (Fig. 1). The X-ray conversion efficiency of phosphor layer, which increases with thickness, is limited because of crosstalk among adjacent pixels. This paper presents a design incorporating a new SU-8 microstructure that alleviates the crosstalk issue.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A CMOS imager with pixel and system level architectures for fast and highly accurate on-chip centroiding has been designed. In-pixel pattern noise reduction and a high gain in-pixel comparator allow for a true weighted average to be computed so centroid accuracies of less than a half-pixel are possible. A high-speed readout scheme makes the potential speed of centroid computations much faster than would be possible in conventional off-chip methods.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The channel length in conventional TFTs (see Fig. 1), which is defmed by photolithography, is subject to errors associated with masking and etching. Additionally, each of the metallization regions occupies approximately an equal part of the TFT area, thus consuming considerable device area. In contrast, the channel length in vertical TFTs (Fig. 1) is defmed by the thickness of the dielectric layer separating the source and the drain, thus enabling sub-micron channel TFT process with no photolithographic constraints.1,23A5 By orienting the metallization regions vertically, the VTFT area can be reduced down to 1/3 of the conventional TFT area based on the same design rules. When incorporated as switching devices in active matrix liquid crystal displays or active matrix flat panel imagers, a considerable reduction in pixel size can be achieved.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Hydrogenated amorphous silicon (a-Si:H) has been widely used in low-temperature large area electronics such as solar cells, active-matrix liquid crystal displays (AMLCDs), and optical or X-ray image sensors for medical applications [1]. In particular, image sensors for diagnostic X-ray imaging are a very promising technology for creation of digital X-ray images, which can potentially replace conventional film imaging technique.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Presently, various aspects of CMOS technology scaling present additional challenges in CMOS image sensor design. Designers require optical as well as electrical models of the CMOS based pixels and the pixel arrays in order to translate given design objectives to proper choices of technology, pixel architecture, array structure, design layout, etc. Toward this end, we present a one-dimensional analysis and a working model of CMOS photodiode emphasizing on the effect of the finite epitaxial thickness and the presence of electric field at the interface between the epitaxial layer and the substrate bulk.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Video is increasingly used in various advanced applications. Many of these applications require common video represen- tations that should be oriented towards how people describe video content. In this paper we first discuss the background of high-level video representations. We then introduce a computational framework for high-level video representation that evolves towards how people describe video content. Our framework represents a video shot in terms of its moving objects and their related semantic features such as events and other high-level motion features. To achieve higher applicability, content should be extracted independently of the type and the context of the input video. Our representation system, implemented on 6371 images with multi-object occlusion and artifacts, produces stable results in real-time. This is due to the adaptation to noise, the compensation of estimation errors at the various processing levels, and the division of the processing system into simple but effective tasks.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We propose and demonstrate the application of coherence modulation of light in shadow casting correlation. This technique allows to carry out simultaneously several correlation products in order to increases the processing capacity of this correlator. The experimental results have been obtained with a broadband source, such as white-light source.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
There is a need to collect field information for surveillance or action preparation purposes in today military activities. In present day, these operations are carried out by personnel or air surveillance with various expensive, sophisticated sensors. However, the large volume of collected data makes it difficult to extract timely interpretations for decision making in time critical scenarios. In addition, as the activity is occurring, it is almost impossible to retask the system to resolve ambiguity in the original data. Moreover, these monitoring are difficult to be maintained in volatile situations and the cost of continuous surveillance is high. Not only such a deployment is risky, it is time consuming to prepare, coordinate, and perform. Therefore, there is a need to develop low cost sensors, which collect and report field information to the base autonomously. This is the motivation behind the concept of Autonomous Microsystems for Ground Observation (AMIGO) currently investigated at Defence Research Establishment Valcartier (DREV). This work is to establish preliminary standard; to design and manufacture prototype microsystems; and to identify strategies and directions for further improvement of the units. These systems differ from their counterparts in that they are mission specific so that the reduced demand in sensing robustness and versatility is translated into simpler, computationally less demanding systems.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The National Research Council (NRC) together with RD-Tech Aero and Universite Laval have been developing a new nondestructive inspection (NDI) system called Intelligent Visual Evaluation (IVE). IVE is based on a new optical sensor technology called Edge of Light (EOL) developed at NRC (Forsyth, D. S., Marincak, A., Komorowski, J. P., Edge of Light: A New Enhanced Optical NDI Technique, Nondestructive Evaluation Techniques for Aging Infrastructure and Manufacturing, Scottsdale Arizona, SPIE Vol. 2945, December 1996, pp. 178-188). EOL is an optically based imaging method that uses oblique angle lighting and obturators to image surface slope changes on the object under inspection. Any phenomenon that affects surface topography can be studied with EOL. Potential spatial resolution and surface slope change resolution are extremely high, yielding a wide range of potential applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Since the discovery of the BiSrCaCuO superconductor,1 the response of this compound to infrared and millimeter wavelength radiation has received particular attention. To promote the growth of the high 11 phase, Pb is usually introduced into this compound.2 In our laboratory, the response of thin BiPbSrCaCuO films has been investigated at temperatures above and below Tc. When the film was biased into a partially resistive regime, a subgap nonbolometric response to millimeter waves was found to occur.3 Lately, a nonbolometric response to thermal infrared radiation was also found in normal state films and was attributed to the tensorial Seebeck effect.4 This paper reports on further evidences of the Seebeck effect and a BiPbSrCaCuO detector that makes use of this effect. BiPbSrCaCuO films were prepared on monocrystalline MgO substrates by magnetron rf sputtering.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Introduction Hydrogenated amorphous silicon thin film transistors (a-Si:H TFTs) are widely used as switching elements in liquid crystal displays (LCDs), imaging arrays and page-width printers that employ the active matrix addressing architecture. These devices, however, suffer from the electrical instability, when a prolonged voltage stress is applied to the TFT gate. This instability appears as a threshold voltage shift and degradation in subthreshold slope. Metastability of amorphous silicon TFTs under DC bias stress has been of interest in previous research, but less attention has been paid to the instabilities induced by pulse bias stress [5][6]. The study of pulse bias induced metastability of a-Si TFTs provides insight for designing circuits that are less sensitive or insensitive to instability. The results allow use of appropriate techniques to compensate for metastability, leading to less degradation from normal operation and longer lifetime for large area electronic systems. The paper presents results on pulse bias induced metastability of several a- Si:H inverted-staggered TFTs fabricated in-house at the University of Waterloo Microelectronics Laboratory using a 260°C fully wet-etch process.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The present paper proposes a new approach for the implementation of a multiresolution CMOS image sensor at the pixel level, in contrast to the previously reported column- and chip-level integrations Ell, [2] The new approach is realized through the implementation of multiresolution acquisition scheme with a new pixel building block in order to sample any arbitrary multiresolution pattern with multiple fields of view. The programmability, expandability and low power properties are the most important features characterizing our new suggested acquisition scheme. Thus, it forges the way for a broad spectrum of applications, from web cameras and videophone to industrial inspection and multi-objects tracking. The new architecture has been implemented on a 64x64 pixel image sensor using 0.18iim standard salicide CMOS technology with six metals and one poly silicon layer occupying 3.5x3.5mm2. The chip is currently under test.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The architecture of an analog hardware spatial filtering system is shown. Coupled with an array of photodiode pixels it may be used as method image smoothing and edge detection. The image kernel is 5x5 pixels and is implemented in analog CMOS circuits using a standard 0.35gm TSMC process.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The polymer light-emitting diode (PLED) has evolved since inception in 1990 [1] to a technology that is now competing with liquid-crystal displays. Fabrication of low-cost, large-area flat panel displays on both rigid and flexible substrates, with high brightness and good contrast at low power consumption have now become possible. This paper describes the fabrication of PLEDs, and in particular, the different processes for achieving patterned layers of conducting polymers. The processes considered here include the widely reported inkjet printing technique and plotting. The latter is demonstrated for the first time in this paper. With both techniques, the ink is replaced with an appropriate polymer solution. Although ink jet printing offers relatively small feature sizes and currently meets the resolution requirements for high information content displays, there are a variety of other application areas (e.g. electronic labeling) which can be met with the plotting technology where resolution requirements are not as critical.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Many biological visual systems have demonstrated that a large degree of image preprocessing takes places at the detector level, making effective use of the spatial arrangement of the detectors that are relatively sparsely interconnected. More sophisticated image processing is then performed in the visual cortex of the brain. Similarly, the aim of many recent work in active pixel sensors (APS) is thus to perform certain image preprocessing steps that can be more efficiently achieved at the detector level using analog circuitry, taking advantage of the parallelism of the image detectors. Its output is then sent to post-processors, often taking the form of digital signal processors.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
1 . The working characteristics and requirement of array servo-transmitting and cavity mirrors for ICF The array servo-transmitting and cavity mirrors are used in target optic system and amplifier for ICF. According the working requirement to the array servo-transmitting and cavity mirrors the characteristics of them are the following: A. The interval between mirrors is small and the mirrors should transmit the laser beam in full aperture without any obstruct; B. The requirement to the sensitivity of adjustment is very high; C. The adjustment should be very simple and fast established; D. The high stability of adjustment in space and time; The primary technical specifications of array servo-transmitting and cavity mirrors are:
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Aggressive R&D and commercialization programs targeting various types of micromirror-based micro-opto- electromechanical systems (MOEMS) have been realized at INO. These activities are accompanied by development of enabling technologies and selected micro-optical components such as various types of diffractive optical elements and refractive microlens arrays. Micro-optics technology development was considered essential for the manufacturing of functional devices and instruments making use of MOEMS. Moreover, a strong contribution from INO's optical design group was also solicited for the development of application specific optical and optomechanical components. These created a required critical mass for rapid development of selected manufacturing methods and particular components and devices. All the microfabrication activities are conducted in INO's 6,500 square foot clean room facility fully equipped for processing of Si and other material wafers with a diameter up to 150 mm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We have demonstrated liquid-crystal WDM (wavelength-division-multiplexing) optical gain flatteners, as shown in Figures 1 and 2. They provide functionality of optical power equalization, tilting and profile manipulation using liquid-crystal modulators and harmonic synthesis approach. Liquid-crystal modulators utilize polarization manipulation without moving mechanical structures to process optical signals. This provides reliability of solid-state technologies. Liquid-crystal material has low absorption in the infrared wavelengths, so the devices could have low and uniform insertion losses over a wide spectral range. Since liquid-crystal modulators manipulate optical polarizations, one can utilize the known polarization states in the optical paths to minimize polarization-dependent losses. These advantages make liquid-crystal devices an attractive option for all-optical WDM signal processing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We here present wide band net gain measurements in a Cd3P2 Cylinder Fiber. These fibers normally absorb light. Pump induced charge cariers first decrese the absorbtion. Further pumping results in net gain. The Semiconductor Cylinder Fiber (SCF) we fabricate consist of a type 7056 glass core with a diameter of 9.6 pm and an index of refraction of 1.487. The core is surrounded by a thin, 5 to 15 nm thick, semiconductor layer. The semiconductor layer in turn is surrounded by a type 7052 glass cladding with an index of refraction of 1.484. The fiber has an outside diameter of 84 yam, Fig. 1.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Increasingly, photonic integrated circuits (PIC) are used in optical networks. Photonic integrated circuits (PICs), which combine a number of optical elements on a single chip, are becoming more important due to their compactness and large-scale production. Packaging problems are also reduced due to integration in PIC.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A fiber grating prism (FGP) consisting of one single-mode fiber delay line and four tunable chirped grating delay lines is proposed and demonstrated. This FGP can provide five-channel time-delayed signals that can be fed to an antenna array to achieve continuous beam scanning. The proposed true-time-delay unit with 5-element phased array steerer is suitable for beamforming at frequencies up to 18 GHz.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We have demonstrated a widely tunable fiber Bragg grating filter which operates the full C- band. The device is based on stretching of the fiber Bragg grating to induce the wavelength change. The device has great potential for optical add/drop multiplexing applications and DWDM channel monitoring.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Narrow-linewidth, wavelength tunable fiber lasers operating in the 1550-nm band have important applications in high-capacity communication systems, especially in wavelength-division-multiplexing (WDM). Such lasers will also have applications in optical sensors, high-resolution spectroscopy and photonics true-time-delay beamforming systems". In this paper, we report a wavelength tunable narrow linewidth single-wavelength Erbium-Ytterbium co-doped linear-cavity fiber laser using a chirped fiber Bragg grating combined with a novel switchable fiber Bragg grating (FBG) array. In this configuration, the chirped fiber Bragg grating acts as a partial-reflecting mirror and the switchable FBG array acts as the full-reflecting mirror and wavelength selector. The switchable FBG array consists of a 1x3 optical switch and three parallel discrete FBGs. The reflection wavelengths of each discrete FBG can be continuously tuned in a range of over 15 nm by stretching (7 nm) and compressing (8 nm) the FBG. Therefore a fiber linear-cavity laser with a very large wavelength tuning range can be successfully demonstrated. In our experiment, the wavelength tuning range of the fiber linear laser is 30 nm, from 1535 nm to 1565 nm. Within this tuning range, the total output power is about 6 dBm, the 3-dB linewidth is 0.01 nm, and the side mode suppression ratio is more than 30 dB.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper presents results of the numerical modeling of a passively Q-switched intracavity harmonic generator as a source for laser micromachining. The model is based on the system of coupled rate equations for the active laser medium, passive Q-switching element, laser mode and mode of the generated harmonic. Main features of the system behavior (pulse shape and duration, repetition rate) were investigated numerically. Numerical investigations of the interaction of laser pulses generated by this system with metal target with focus on the laser pulse width dependence are presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Micro electrostatic actuators play an important role in driving optical MEMS devices such as spatial light modulators, micro mirrors, and MEMS tunable lasers. The wide acceptance of electrostatic actuators is due in large to the fact that they are simple, they offer a fast response and low power consumption, and are potentially cheap when high volume is involved [ l ] -[3 ] .
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
With the development of innovative manufacturing techniques, next-generation fiber Bragg grating (FBG) components can now be produced with the level of performances and reliability that allow mass deployment of these devices for high-end applications. Gain flattening filters (GFF) with low-error function, low-dispersion WDM filters suitable for operation at 40 Gb/s and low group delay ripples multichannel chromatic dispersion compensators are among these high-end applications. Moreover, since FBG is an all-fiber technology, tunability can be easily implemented opening the door for applications such as tunable chromatic dispersion compensator. In this paper, we will present an overview of those high-end applications and show that FBG technology is well suited to overcome the challenges imposed by future optical networks.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A Mach-Zehnder interferometer based optical switch constructed in a rib waveguide in SOI is analyzed from optical, electronic and thermal viewpoints. It is shown that fast electrooptic switching can be made to dominate over slower thermooptic effects provided recombination in the diode is minimized.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We demonstrate a novel approach to multi-channel tunable dispersion compensation based on multicavity all-pass etalons that can compensate all channels throughout the C or L band with channel spacings from 50GHz to 200GHz, for either 10Gb/s or 40Gb/s applications. We demonstrate very low group delay ripple, large tuning range, low losses, as well as dispersion slope compensation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
An efficient and accurate model of a distributed feedback laser integrated with an electroabsorption modulator is established. Good agreement between the calculated and measured results for the time-resolved chirp is achieved.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In this paper, we introduce the design of a microshutter based on the electro-thermally actuated mechanism. The U-shaped folded beam device consists of a "wide cold" beam and a "narrow hot" beam. The end of the beam is a blade structure, which serves as the shutter part. When current is passed through the microshutter between two mechanically anchored electrode pads, the non-uniform Joule heating causes the whole structure to bend toward the "wide cold" beam. Also in this paper, we present a study and design of a novel bi-directional microswitch. The design has two identical beams and can bend in two directions by controlling the direction of the applied current. Finite element modeling (FEM) is used to visualize the function of these devices. The geometry of the membrane and the structure play important roles in the functionality of these devices.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The role of wavelength division multiplexing (WDM) in telecommunication networks can be expanded well beyond providing high capacity on point-to-point transmission links. WDM can be used to perform network functions such as routing, switching and add/drop multiplexing. The optical add/drop multiplexer (OADM) is a key component for WDM networks. An OADM adds and drops one or more of the signals in a wavelength division multiplex of optical signals without interfering with other channels on the fiber. Different approaches are available for implementing OADMs. These include thin film filters, arrayed waveguide gratings, circulators with fiber Bragg gratings (FBGs), and FBGs in the arms of a Mach-Zehnder interferometer (MZI). Fig. 1 shows configurations of add/drop multiplexers that use fiber Bragg gratings with two different resonant wavelengths'. One configuration is based on an MZI and FBGs, and the other is based on circulators and FBGs. In order to add/drop more than one channel, a multiple number of narrowband gratings are used. Imperfect reflection of the FBGs at the resonant wavelengths will introduce multipath interference from the reflections at discrete points. This is referred to as interferometric noise. 201 and 202 are the selected wavelengths for add/drop and correspond to the resonant wavelengths of the gratings.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Plasma-enhanced chemical vapor deposition was used to deposit titanium dioxide (TiO2), silicon dioxide (SiO2) and Ti02/Si02 mixtures films with any index of refraction between 1.50 for SiO, and 2.35 for TiO2. We fabricated simple inhomogeneous and multilayer filters, namely rugate filters and quarter-wave stacks, as well as more sophisticated inhomogeneous filters, multiband rugate filters. We showed that inhomogeneous filters cause less light scattering than their multilayer counterparts.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
JGKB Photonics Inc. and the University of British Columbia present recent results for an alternative type of electro- optic modulator, the integrated-optic mode-converter [1]. The integrated-optic mode-converter has the potential to bring the drive-voltage of electro-optic modulators down to the 3 to 4 V range while preserving the benefits typically associated with LiNbO3-based integrated-optic Mach-Zehnders, e.g., low insertion loss and low chirp, and while being fabricated in compound semiconductors such as GaAs or possibly InP (i.e., these devices are based on mature, stable semiconductor technologies). Such devices are shown to operate at ultrahigh-speed, having electro- optic bandwidths in excess of 40 GHz.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The understanding of the nucleation stage of thin film growth is a key element of the optimization of synthesis parameters in order to obtain high-quality optical coatings with predetermined characteristics. The fabrication of advanced coatings, often consisting of complex non-quarter wave and/or metal dielectric stacks, requires new and more powerful in situ monitoring techniques compared to conventional reflectometry and transmission, or quartz crystal microbalance measurements. We describe the use of in situ real-time spectroscopic ellipsometry (RTSE) for the development of optical materials and for the control of the fabrication of homogeneous and inhomogeneous optical filters. Examples include materials such as Ti02, Si02 and SiNx prepared by plasma-enhanced chemical vapor deposition (PECVD).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper examines the influence of the total pressure and the various gas flow rates on the composition of thin silicon - oxynitride films, as expressed through their refractive indexes. These aspects are highly relevant to producing high quality and reproducible films for optoelectronic applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The purpose of this presentation is to describe an optical set up developed to measure axial stress in optical fibers and all fiber devices. It is believed that knowledge and control of residual stresses will impact the future development of all fiber components. Single mode fibers used in optical devices usually have two vectorial propagations modes. A stressed induced non-uniform index distribution will affect the following parameters: polarization mode dispersion, polarization dependant loss and mode coupling ratio in optical devices. Those effects have to be well characterised due to recent increases in bit rate of optical transmission systems requiring better component performances. In this paper, we will explain how our measurement system works and show some preliminary results.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A new architecture of four pass amplification system for main amplifier stage of ICF driver was tested with I x2 amplifiers in the aperture of 240x240mm2. A compact plasma-electrodes Pockels cell(PEPC) was first adopted in beam reverser. The preliminary experiment results testified this architecture and provided a approach to build big laser drivers.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The fusion process of the fused-fiber couplers is considered as the motion of an incompressible Newtonian fluid, which is driven by a constant surface tension acting at the free boundary. The internal velocity field is obtained using conformal mapping methods introduced by Hopper and Richardson. Markers are then used, to determine the layers' shape evolution. Theoretical results are compared to experimental observations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The packaging of optoelectronic components presents many challenges related to the optical alignment of optical and optoelectronic components, due to very precise placement requirements, the demand for long term reliability and environmental insensitivity, and also for a fast and cost effective packaging process. This paper focuses on techniques used for precise optical alignment and the challenges related to their use, analyzed in the context of the whole optoelectronics packaging process.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Spectroscopic ellipsometry is a technique that is powerful for characterizing thin films and materials. The technique is now routinely used in R&D laboratories for characterizing a very wide diversity of thin films and materials, and within manufacturing facilities for monitoring deposition processes. Spectroscopic ellipsometry relies on the determination of the polarization state of an incident beam upon reflection on the sample under characterization. When performing spectroscopic ellipsometry, the polarization state is determined at many discrete wavelengths over a broad spectral range. The change in the polarization state can be traced to the physical properties of the thin film by means of a model and through regression analysis. Physical characteristics such as layer thickness, surface roughness, index of refraction and coefficient of absorption of the materials can be determined with excellent precision. The principle of the technique is outlined in Fig. 1.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper sets out to examine the internationalization processes of a sample of companies drawn from a cluster of photonics companies. Twenty CEOs were interviewed, face to face. Using content analysis combined with a grounded theory influenced approached the texts of these interviews were appraised. In this way the internationalization theory was critiqued and some insights developed into the international strategy process. Some salient findings emerged, some of strategic significance to the companies in the photonics cluster.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The Rochester, NY regional photonics industry is in a period a technological and organizational change. Over the past seventy years the regional has enjoyed a reputation as one of the premium optics and imaging (photonics systems) centers of the world. In the past, the driving force behind this preeminence was a small number of larger diversified companies with strong technological competencies and internally oriented operations. Supporting these firms were dozens of small optics, components, and imaging suppliers who grew and declined with their primary customers. Today's competitive photonics industry is far different technologically and organizationally then what existed 20 to 40 years ago.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
To determine the full cost of purchasing and operating manufacturing equipment and its potential return on investment (ROI) component manufacturers are being forced to look beyond the initial purchase price of the equipment. The cost of operating and maintaining the equipment over its lifetime often exceeds the original purchase price by several times. In order to determine the real costs associated with the purchase of assembly equipment one needs to take into account such things as throughput rate, yield, reoccurring costs such as labor and maintenance costs as well as determine the utilization of the equipment. In order for optical component manufacturers to be able to lower their manufacturing costs they first need standardized methods for analyzing the cost breakdown of the manufacturing process into finite elements that contribute to the cost per manufactured part. One widely accepted method of performing this type of analysis is to use the principles of the SEMI E35 standard for determining the Cost of Ownership (COO). In its simplest form COO determines the total capital outlay over the life of the equipment divided by the number of good parts produced as depicted in formulas below:
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper sets a framework for building value in new ventures. And it will delineate the cornerstones of a solid venture such as science validation, technology development, creating intellectual property, quantifying market opportunity, capital financing and human resources.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The photonics industry at present seems to be characterised by depressive chaos. Particularly in the telecommunications sector, what was perceived as a paradise of limitless growth has turned into a desert where shambling relics of formerly great companies stagger towards an unknown horizon, hoping for some signs of growth.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Education in Ontario is undergoing a period of rapid change and we have been successful in providing support to local and provincial educators teaching grades 6 through 12. The Southwestern Ontario Section of the Optical Society of America is a local section of the parent organisation, whose members come from industry and academia. Ours is the second section established in Canada and we recruit both student and professional members with an interest in optics and photonics. The Optical Society of America encourages local sections to include educational outreach in their activities. We are undertaking a multi-faceted effort to accomplish this.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Scientists and engineers who can design and operate optoelectronic components and systems are in demand in the photonics industry. Optical fiber links are crucial to all parts of telecommunications systems, from the global Internet and increasingly in local area networks. One of the challenges facing educationalists particularly in this area, is to design practical experiments at an appropriate level that provide students with the opportunity to investigate basic principles, characteristics, and design of optical waveguides. However, optical equipment can be very expensive and our goal here is to create an advanced experiment, suitable for use in an upper level undergraduate laboratory, balanced against the constraints of a typical academic teaching budget.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Photonics related industries in Canada have enjoyed remarkable success in the last decade, particularly in the area of fiber optic telecommunications. There is, however, growing concern that a shortage of highly skilled photonics professionals will limit future growth and weaken Canada's competitive position. A recent paper by Nantel and Beda' presents a good summary of the state of photonics in Canada and the projected needs for highly qualified personnel. The recent economic downturn, which has been particularly severe in the photonics sector, has reduced the sense of urgency surrounding the projected shortages of highly qualified personnel. Many individuals who were recently recruited into the photonics industry are now seeking other employment. This should serve as a warning to university educators not to focus their programs too narrowly on specific short term requirements of industry, but to provide graduates with a broad skill set that leaves them positioned to react to changing circumstances. Nevertheless, the critical importance of photonics education and training and the long term prospects in this sector remain unchanged. To meet the future demands for skilled professionals, there is a need for more bachelor's level university programs that include advanced photonics concepts and exposure to state of the art technology.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The shortage of skilled photonics professionals limits growth The rapid growth of the photonics sector has far outpaced the ability of education and training providers to produce graduates with critical skills in optics and photonics. The acute shortage of technical professionals is a large factor in limiting the growth of the industry. The eMPOWR (Microelectronics, Photonics/Optoelectronics, and Wireless/Radio engineering) initiative has conducted a large-scale survey and estimates that by the year 2005, Canada will be short 70% of the number of highly qualified people that will be needed to maintain the present growth of eMPOWR sectors, including photonics.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
When there is a shift from one revolution to another, there are major shifts in the elements that comprise these revolutions. The industrial society was characterized as mass production requiring few professionals, with little requirement for a wide range of professions and little need to re-skill over time. In contrast, the knowledge society has a greater demand for more professionals, uses a wide variety of professions, and is characterized by rapid cycles, changes and varying skills need.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Corporations are looking for maximum value for time and money invested in training. One way to provide this is to customize training to the specific needs identified by the client. However, without basic optics knowledge, explaining the complex fiber optics devices in use today is difficult. This presentation discusses possible solutions to this dilemma.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The fast growth of the photonics industry in the past several years has lead to great demand on professionals in the field of optical science and engineering. In response to this market demand, many universities have enhanced, to a certain degree, their photonics related programs in an effort to produce graduates with some degree of knowledge of photonics. A few universities in the US and Europe have gone even further creating new program specifically in photonics/optical science or engineering. However, we have not seen this type of programs being created in Canada so far. At Wilfrid Laurier University (WLU), we have conducted research on the photonics related programs in Canada, USA, and Europe. We have found that the Department of Physics and Computing at WLU has a unique position and a great opportunity to create the first Canadian Honours B.Sc. Degree Program in Photonics Science. We feel that dual nature of physics and computing of our Department offers the best combination for such a program. In this paper, we discuss the following items: (1) The curriculum of the Honour B.Sc. degree program at WLU. (2) Is a degree in photonics too narrow? (3) Issues related to enrolment, graduates, and potential jobs opportunities.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Optical Coherence Tomography Optical Coherence Tomography (OCT) is a novel imaging technique that is analogous to ultrasound imaging with low coherence, near-infrared light waves. It holds the potential to provide researchers and medical clinicians with in vivo, real-time images with sub-cellular resolution (5 - 10 microns). These images can be acquired non-invasively and without damage to the sample. OCT promises to advance state-of-the-art microstructural and functional imaging for bio-medical applications with in vivo visualization of individual cells or cell clusters in intact tissues. The ability to perform real-time, non-invasive "histopathology" can have a major impact on research and clinical management.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.