This PDF file contains the front matter associated with SPIE Proceedings Volume 6716, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference and Symposium Committee listings.

Many methods for spectroscopy signal analysis have been employed to extract useful and correct signals from measured data, such as Fourier analysis, wavelet analysis and so on. However, Fourier analysis is only suitable for stationary signal processing. Although wavelet transform is capable of analyzing non-stationary signals, many deficiencies have been reported in the use of wavelet transform. Non-adaptive nature is one of its disadvantages. Once the basic wavelet is selected, one will have to use it to analyze all the data. And the number of levers that the signal will be decomposed into must be decided by user and the frequency bands of all lever signals are fixed. Due to the deficiencies of wavelet transform, Huang et al. proposed a new type of signal processing method called empirical mode decomposition (EMD), with which any complicated data set can be decomposed into a finite and often small number of Intrinsic Mode Functions (IMFs). This method is suitable for non-linear and non-stationary data processing and has advantages that wavelet analysis has. In this paper EMD method is used in spectroscopy signal processing. And it is just in the infant period for spectroscopy signal processing. In order to verify the rationality and feasibility of EMD, polystyrene thin film is chosen as the testing sample. Its reflection interference spectroscopy is collected by the spectrometer made by Ocean Optics Company. And then the EMD approach for processing the reflection interference spectrum of polystyrene film is discussed. The sifting process in EMD can be stopped by predetermined criteria. And the number of IMF is selfadaptive. For choosing suitable number of IMF, the variance standard has been selected in this paper, with which the quality of the processing results can be optimized. Then the thickness of the polystyrene film can be calculated from the extracted spectrum by EMD. Comparing the thickness with the calibrated value, the error is below 1%, which proved that the proposed method is efficient and accurate in spectroscopy signal analysis.

This paper proposes a new arrangement for an interferometric laser‐speckle gauge. For the proposed set‐up geometrical inaccuracies are assumed. Therefore, we are looking for a sensor position, where the geometrical inaccuracies are having the smallest impact on the measurement result. For the measurement of an applied measurand vector to the observed specimen, we suggest a linear unbiased minimum variance estimator. Theory an measurement results using this estimator are shown for a specific measurement set‐up of the laser‐speckle strain gauge.

The Portevin-Le Châtelier (PLC) effect is a case of plastic instability that may occur during the deformation of ductile alloys. The phenomenon is usually investigated by means of tensile tests, in which, for certain ranges of temperature and strain rate, the plastic deformation of the material intermittently loses the uniformity and concentrates in narrow regions. These regions are referred to as PLC bands. In the recent years, great attention is given to the characteristics of these bands, which are often studied with optical methods. With the aim of improving the resolution of these observations, the employed camera should frame a small region of the material, but this leads to the drawback that the rest of the specimen is not considered. To overcome this limitation, the propagating nature of the bands can be profitable since one can predict the position and the time of the next event and then move the camera accordingly. In this paper an optical measuring system is presented, permitting the tracking and observation of a certain type of PLC bands. The system consists of two cameras, one for a global observation of the specimen and a real time detection of the emerging bands, and a second one for the detailed observation with a high resolution. This last camera is moved along the specimen in order to continuously image the propagation of the band.

Process engineering and failure analysis of MEMS and MOEMS require static and dynamical characterization of both their in-plane and out of plane response to an excitation. A remarkable characteristic of Digital Holography Microscopes (DHM) is the extremely short acquisition time required to grab the whole information necessary to provide 3D optical topography of the sample: a unique frame grab, without any vertical or lateral scan provides the information over the full field of view. First, it ensures DHM measurements to be insensitive to vibrations. Second, it opens the door to fast dynamical characterization of micro-systems. For periodic movement analysis, DHM can operate in two stroboscopic modes with standard cameras. The first one enables precise characterization up to excitation frequencies of 100 kHz with recovery cycle of 10% simply by triggering properly the camera. The second one uses a pulsed source for investigation of higher excitation frequencies. For non periodic movement analysis fast acquisition cameras and postponed treatment are used. DHM are therefore unique and very efficient tool for dynamical characterization of in‐plane and out-of-plane response. In this paper we illustrate the two stroboscopic modes with an example of a high frequency micro mirror.

This paper describes a real-time system for measuring the three-dimensional shape of solder bumps arrayed on an LSI chip-size-package (CSP) board presented for inspection based on the shape-from-focus technique. It uses a copper-alloy mirror deformed by a piezoelectric actuator as a varifocal mirror enabling a simple, fast, precise focusing mechanism without moving parts to be built. A practical measuring speed of 1.69 s/package for a small CSP board (4 x 4 mm²) was achieved by incorporating an exclusive field programmable gate array processor to calculate focus measure and by constructing a domed array of LEDs as a high-intensity, uniform illumination system so that a fast (150 fps) and high-resolution (1024 x 1024 pixels/frame) CMOS image sensor could be used. Accurate measurements of bump height were also achieved with errors of 10 μm (2σ) meeting the requirements for testing the coplanarity of a bump array.

The technique of surface profile measurement using white-light interferometry is widely used in industry. However, its application to transparent thin films has been limited to date because the reflection signals from the front and back surfaces are mixed and must be separated in order to obtain correct measurements. This paper introduces four of our recent developments in this application field: 1) profiling of a thick transparent film, 2) profiling of a thin transparent film, 3) thickness profiling of a freestanding film, and 4) simultaneous measurement of the thickness and refractive index of a freestanding film.

We present a method to achieve real-time dual-wavelength digital holographic microscopy (DHM) measurements of micro-electro-mechanical systems (MEMS) with a single camera acquisition. Indeed, while DHM is a technique of choice for MEMS investigation, thanks to its high-speed full-field complex wavefront reconstruction compatible with stroboscopic or pulsed operation modes, the nanometer-resolved phase information available suffers from a so-called phase ambiguity when the optical path length (OPL) induced by the sample is larger than the laser wavelength (typically 400-700nm in the visible range). This measurement range limitation is due to the periodic nature of the phase and, although unwrapping algorithms may be used in some cases, it represents an obstacle to widen DHM applications range. Here we introduce a technique for two-wavelengths DHM, extending the technology field of applications to the micro-meter range, and this with a single hologram acquisition to stay compatible with the exclusive DHM high-speed capabilities described above. Examples of investigation on a 1Hz moving micro-mirror at video frequency are shown to demonstrate the interest of the method for MEMS monitoring.

Currently, backlighting units have been studied widely for the uniform light source of flat panel in LCD display industry. Due to size, uniformity and efficiency of illumination source, traditional backlighting units composed of fluorescent lamps have been replaced with LED backlighting units gradually. In small display markets of cell-phone, PMP, PDA, etc., small-size LEDs are generally used for backlight units' illumination part. For their uniform light-emitting, the volumetric size control of each one's pocket is crucial in LED manufacturing process, because the pocket fills with the transparent molding material for protecting led die and bonding wire in final manufacturing stage. Here, we present a three-dimensional vision system for volumetric inspection of LED pocket. Because of the high ratio of outside wall's height to inside base's width, conventional measurement techniques easily produce noisy results due to the shadow problem. For preventing this effect, the proposed sensor system utilizes dual projection system. By using two measurement results acquired from projection with different incident angles, the shadow-free results can be acquired finally. In this paper, we will describe the sensor system's principle and the sensor fusion algorithm combining two measurement results. After a series of experiments, the measurements results are discussed in depth.

An elaborated mechanism for sheath flow forming includes flow cell, vacuum pool, sample pool, syringes, valves, and tubes. Firstly the sample is drawn into the sample inlet of flow cell through vacuum generated with one syringe. Then, the sample and buffer are driven to pass the flow cell to form sheath flow by other two syringes. To visualize and evaluate the sheath flow, black ink is used as sample, and optical imaging system is adopted to capture the formed sheath flow. Sheath flows with sample width of 21μm and 37μm in diameter are formed in a flow cell with micro-square hole of the size 0.2mm×0.2mm when the syringes run in different speed.

A theoretical approach to study the influence of temperature stress of the thermal sensitivity effective refractive index for asymmetrical nonlinear optical waveguides is developed. In the proposed waveguide structure, temperature stress is induced due to the different thermal expansion coefficients of the substrate, core and cladding. Numerical calculation is carried out to draw the thermal sensitivities of effective refractive indices against the core thickness for both transverse electric modes (TE) and transverse magnetic modes (TM). The relation between thermal sensitivities and different temperature stress gradient is derived and plotted. Based on the results, thermal sensitivity of the sensor can be controlled by temperature stresses which can be controlled by carefully picking the materials and loading methods.

In recent years, designing of multi-channel optical filters has become an essential and inseparable part of wavelength-division-multiplexing (WDM) and dense wavelength division multiplexing (DWDM) systems. In this paper, efficient design of multi-channel optical filters using superimposed Bragg gratings is investigated. We use Transfer Matrix Method (TMM) for designing where resulted reflection spectrum is apodized with sinc function. For loss compensation, by choosing suitable sinc parameter (k=0.3), sidemode suppression ratios (SMSRs) of approximately 60 and 55 dB are computed for single-peak and 9-peak filters respectively. The rest of specifications of designed filter are: 9 channels with 1.55 μm central wavelength and 1 nm channel spacing. We show that superimposed Bragg grating can be used to design efficient multi wavelength optical filters with arbitrary characteristics.

This paper will detail novel enabling fiber optic sensors based on the use of the photonic structures embedded in the core of the fiber. We will start by briefly reviewing fiber optics used as sensors for mechanical deformations, and introducing photonic crystals characteristics. Afterwards we will show that embedding photonic crystal structures into standard monomode fiber optics allows for highly sensitive detection of mechanical deformations. Finally, we will show simulation results using EMExporer which support our claim that embedded photonic crystals can sense very small mechanical deformations.

Near-field microscopy applications sometimes require scanning the sample over the millimetre range. This paper describes a home-made displacement system that can replace the limited range XY scanner of a classical near-field microscope. The system lays on a coarse/fine displacements configuration to attain the millimetre. Nanometre scale repeatability and resolution are met thanks to a control loop based on phase shifting techniques. The system was tested under an Atomic Force Microscope. The setup of the experiments and the results obtained are herein presented.

The space mission LISA (Laser Interferometer Space Antenna) aims at detecting gravitational waves in the frequency range 30 μ Hz to 1Hz. Free flying proof masses inside the satellites act as inertial sensors and represent the end mirrors of the interferometer. In the current baseline design, LISA utilizes an optical readout of the position and tilt of the proof mass with respect to the satellite housing. This readout must have ~ 5pm/√Hz sensitivity for the translation measurement (for frequencies above 2.8mHz with an ƒ^-2 relaxation down to 30 μHz) and ~ 10 nrad/√Hz sensitivity for the tilt measurement (for frequencies above 0.1mHz with an ƒ^-1 relaxation down to 30 μHz). The University of Applied Sciences Konstanz (HTWG) ‐ in collaboration with Astrium GmbH, Friedrichshafen, and the Humboldt-University Berlin ‐ therefore develops a highly symmetric heterodyne interferometer implementing differential wavefront sensing for the tilt measurement. We realized a mechanically highly stable and compact setup. In a second, improved setup we measured initial noise levels below 5 pm/√Hz and 10 nrad/√Hz, respectively, for frequencies above 10mHz.

In this paper, we present a new concept of 3 Degrees Of Freedom (3-DOF) sensors, which are capable of measuring the absolute position X-Y with a resolution less than 0.16μm (defined here as 4σ and σ denotes the standard deviation) and the orientation θ_z (over 360°) with a resolution of 0.48'. The principle of this low-cost and small-size 3-DOF sensor relies on a target with a specific pattern that includes periodic absolute position information that can be used to enhance the position resolution by statistical analysis. Efficient image processing algorithms are applied to improve both the reliability and the resolution of the target positioning and are optimized in term of processing complexity (i.e., time of processing).

New generation of light fibers: Photonic Bandgap fibers (PBG fiber) were applied as gas cells in the concentration measurement sensor. Several types of PBG fibers of various parameters were designed. Core diameters ranged from 10.9 to 26.25 μm. The precise cutting method for the PBG fiber was proposed. Capillary gas flow rate within the fiber was simulated and measured. Attenuation of newly produced fibers was investigated and concentration of ammonia gas was measured using the new type sensing system.

In this paper we present a novel sensor device which can be used in a tracking system. Due to its unique design the device can replace the often used assembly consisting of a beam splitter and a quadrant diode. So, it is cost effective and eliminates the power loss introduced by the conventional assembly completely. The sensor array is not only restricted to tracking units but can also be used in other applications where beam positioning without power loss is essential. So, e.g. an online beam alignment during a measurement in microscopy is possible. Several beam profiles are supported due to the possibility to adjust the sensing elements mechanically. Furthermore a miniaturized integrated version of the device is achievable by the usage of microsystems technology.

This paper describes a monocular PSD-based motion capture sensor to employ with commercial video game systems such as Microsoft's XBOX and Sony's Playstation II. The system is compact, low-cost, and only requires a one-time calibration at the factory. The system includes a PSD(Position Sensitive Detector) and active infrared (IR) LED markers that are placed on the object to be tracked. The PSD sensor is placed in the focal plane of a wide-angle lens. The micro-controller calculates the 3D position of the markers using only the measured intensity and the 2D position on the PSD. A series of experiments were performed to evaluate the performance of our prototype system. From the experimental results we see that the proposed system has the advantages of the compact size, the low cost, the easy installation, and the high frame rates to be suitable for high speed motion tracking in games.

We introduce two types of optical fiber Bragg grating sensor with nanoscale spatial resolution and chemical specificity. This sensing technique holds promise for gaining deeper insight into the functionality of nanoscale structures superposed on the gold thin film or embedded in its complex environments. The techniques are based on the effect of surface plasmon resonance and surface plasmon resonance fluorescence. Properly p-polarized laser light illuminates the Bragg grating and induces a strongly enhanced field at the gold thin film. This is due to the coupling of guided mode of the optical fiber and surface plasmon mode. The laboratory prototype of sensor with linear Bragg grating is used for the measurement of smooth variances in refractive index and a sensor with oblique Bragg grating combined with the Scanning near field optical microscope is used for the measurement of analyte thickness. Here, the spatial resolution is determined by the tip size (typically on the order of 60-80 nm).

In this paper, we investigate induced crosstalk due to cross phase modulation (XPM) in optical fibers in the presence of optimal compensation of dispersion. We have already shown that there is an optimal group velocity dispersion curve (GVD) for best compensation. In this paper, we evaluate effect of this type of dispersion compensation from XPM point of view. Also, we compare different compensation profiles for GVD with optimal proposal for GVD. It is shown that optimal GVD introduces smaller distortion compared to other types of profiles. All theoretical investigations are done using the Volterra series.

In this paper effect of parameters of introduced defect in photonic crystal on waveguiding properties are investigated. For this case 2-D photonic crystal structure is considered. Introduced defects are regular and irregular. These types of defects are studied and their effects on waveguiding properties are evaluated. It is shown that introducing defects cause the changes in the bandwidth and amplitude of the structure, and would lead to creation of new transmission bands in reflection band. For evaluation of the effect of introduced defects finite difference time domain (FDTD) method is used.

The main aim of this work is to allow the automated but nevertheless flexible sensor guided micro assembly with a new 3D vision sensor. The practical application of the sensor guided assembly of micro systems is realised with a special micro assembly system, which contains a parallel robot, an innovative 3D vision sensor, micro grippers and workpiece fixtures. The 3D vision sensor, which is arranged directly above the assembly place and moved synchronized to the micro gripper, makes the uninterrupted observation of the workpiece and the determination of its position possible, in this way allowing the sensor guided assembly of micro systems and a detailed analysis of the principles in the micro assembly process. The basic principle of this photogrammetric measurement concept is given through the fiducial marks. The circular fiducial marks will be realised within the photolithographic production of the components. Using these fiducial marks it is possible to measure the relative position of the components during assembly without reference to their exterior shape.