This PDF file contains the front matter associated with SPIE Proceedings Volume 6470, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

We used intrinsic Second Harmonic Generation (SHG) by fibrillar collagen to visualize the three-dimensional architecture of collagen fibrosis at the micrometer scale using laser scanning nonlinear microscopy. We showed that SHG signals are highly specific to fibrillar collagen and provide a sensitive probe of the micrometer-scale structural organization of collagen in tissues. Moreover, recording simultaneously other nonlinear optical signals in a multimodal setup, we visualized the tissue morphology using Two-Photon Excited Fluorescence (2PEF) signals from endogenous chromophores such as NADH or elastin. We then compared different methods to determine accurate indexes of collagen fibrosis using nonlinear microscopy, given that most collagen fibrils are smaller than the microscope resolution and that second harmonic generation is a coherent process. In order to define a robust method to process our three-dimensional images, we either calculated the fraction of the images occupied by a significant SHG signal, or averaged SHG signal intensities. We showed that these scores provide an estimation of the extension of renal and pulmonary fibrosis in murine models, and that they clearly sort out the fibrotic mice.

The synthesis of molecules consisting of various combinations of phenylene and thiophene groups and the subsequent vacuum growth of needle-shaped nanoaggregates on specific surfaces allows us a systematic investigation of the transition between single parallel and multiple aligned needle ('nanofiber') growth. The former growth mode is observed for blue light emitting phenylene fibers, whereas the latter growth mode appears for single crystalline fibers made from green- and orange-light emitting oligo-thiophenes and thiophene/phenylene co-oligomers. In all cases the tailored bottom-up growth results in strongly polarized light emission along specific surface directions. The results are compared to those found for nanoaggregates made from less rod-like organic molecules, namely rubrene and POPOP.

We show that in the presence of fullerene complexes the optical properties of PbS QDs are significantly modified. The absorption of the PbS QDs is observed to shift to a higher energy when fullerene complexes are introduced. Upon direct excitation of the PbS below the fullerene absorption a corresponding blue shift in PL spectra of the PbS QDs is observed. The strength of this blue-shift can be related to the fullerene concentration in most cases and is accompanied by a broadening of the emission spectrum. When exciting the samples at high energy 3.4 eV (363 nm) the strength of these effects is increased with a maximum blue-shift in the PL spectrum of 261 meV and 167 meV occurring for the C₆₀ and PCBM doped samples respectively. The origin of the observed behavior cannot be confirmed at this time and is the focus of ongoing studies. However, we briefly discuss the results obtained in relation to the strong electron accepting nature of the fullerene complexes used.

We report the first observation of unanticipated photoelectric effects (PE) under visible and near-infrared illuminations and diode-type rectifying current-voltage (I-V) characteristics in DNA-metal contact devices. These devices are constructed with DNA film sandwiched between gold (or some other metal) and transparent conductive ITO electrodes. Since the gold work function and the bangaps of ITO and DNA are greater than 4 eV, in order to release an electron in these materials, the photon energy must be greater than 4 eV, indicating an ultraviolet light source is needed. To explain these phenomena, we hypothesize that a Schottky barrier was formed at DNA-gold interfaces when the gold layer was deposited on the soft DNA film during the sputtering process. The Schottky barrier could replace the gold work function in the DNA-gold interface and greatly reduce the potential barriers. The lowered Schottky potential barrier allowed the electrons, excited by lower photon energies, to overcome the barrier into the conduction band and generate photocurrent. The observed photoelectrical effect was used to measure a ~1.52eV Schottky barrier height in DNA-gold contacts. Furthermore, we measured static I-V characteristics of the DNA-metal devices showing typical diode-rectifying behaviors. The observed photoelectrical effect and I-V characteristics strongly suggest a Schottky barrier at the DNA-metal interface.

Organic field-effect transistors (OFETs) currently utilize organic semiconductor materials with low electron mobilities and organic gate oxide materials with low dielectric constants. Compared to inorganic FETs, OFETs have slow operating speeds and high operating voltages. In this paper we discuss blending the conductive polymer polyethylene dioxythiophene (PEDOT) with deoxyribonucleic acid (DNA), with minimal optimization to produce a new bio-conductive polymer complex potentially suitable for OFETs. The conductivity of this new bio-conductive polymer complex is tunable, ranging from 10^-10 S/cm to 10^-3 S/cm at room temperature.

A new capacitive test structure is used to characterize biopolymers at microwave frequencies. The new test structure is comprised of a parallel plate capacitor, combined with coplanar waveguide-based input and output feed lines. This allows electrical measurements to be taken easily under an applied DC electric field and at various temperatures. The dielectric properties are characterized for two biopolymer thin films: a deoxyribonucleic acid (DNA)-based film and a bovine serum albumin (BSA)-based film. These bio-dielectric thin films are compared with a standard commercial polymer thin film, poly[Bisphenol A carbonate-co-4,4'(3,3,5-trimethyl cyclohexylidene) diphenol], also known as amorphous polycarbonate (APC).

A major breakthrough in the area of organic electro-optic (EO) materials has been recently achieved. To go beyond the oriented gas model limit for organic EO materials, new approaches of using nanoscale architecture control and supramolecular self-assembly have been proved as a very effective method to create a new paradigm for materials with very exciting properties. High-performance EO polymers were demonstrated by a facile and reliable Diels-Alder "click" reaction for postfunctionalization and lattice hardening to improve EO activity and thermal stability. This type of "click" chemistry paves the way to systematically study the relationship among EO activity, chromophore shape, and number density of the chromophores. Reversible supramolecular interactions were also introduced to a new generation of EO dendrimers and polymers to create self-assembled nano-objects, overcome strong intermolecular electrostatic interaction, and improve their poling efficiency and stability. These self-organized EO materials were used as hosts in a binary chromophore system to further improve chromophore number density and r₃₃ value. With these novel approaches, we succeeded in enlarging the full potential of organic NLO materials by a factor of 3~5 and developing a variety of nano-structured organic EO materials with ultrahigh r₃₃ values (>300 pm/V at the wavelengths of 1310 and 1550 nm, more than 10 times that of LiNbO₃) and excellent auxiliary property, such as thermal stability and optical transparency. The success of these material developments has inspired the exploration of new device concepts to take full advantage of organic EO materials with ultrahigh r₃₃ values.

Third order nonlinear optical properties (NLO) of thin films of pure DNA-CTMA complex and of those doped with disperse red 1 (DNA-CTMA-DR1) and copper phthalocyanine (DNA-CTMA-CoPc) chromophores were studied by the optical third harmonic generation and as function of the dopant concentration. The THG measurements, performed in vacuum at 1064 nm fundamental wavelength reveal an one orders of magnitude increase of &khgr;⁽³⁾(-3&comega;;&comega;,&comega;,&comega;) susceptibility of the DNA-CTMA complex when doped with 5% of DR1. This increase is less important for the complex doped with CoPc. For both dopants it doesn't follow the chromophore concentration, as it could be expected. This behavior is interpreted in terms of the influence of local field. The &khgr;⁽³⁾(-3&comega;;&comega;,&comega;,&comega;) susceptibility of pure DNA-CTMA complex is about one order of magnitude larger than for silica plate, used as standard.

Fabry-Perot etalons using electro-optic (EO) organic materials can be used for devices such as tunable filters and spatial light modulators (SLM's) for wavelength division multiplexing (WDM) communication systems^1-5 and ultrafast imaging systems. For these applications the SLM's need to have: (i) low insertion loss, (ii) high speed operation, and (iii) large modulation depth with low drive voltage. Recently, there have been three developments which together can enhance the SLM performance to a higher level. First, low loss distributed Bragg reflector (DBR) mirrors are now used in SLM's to replace thin metal mirrors, resulting in reduced transmission loss, high reflectivity (>99%) and high finesse. Second, EO polymer materials have shown excellent properties for wide bandwidth optical modulation for information technology due to their fabrication flexibility, compatibility with high speed operation, and large EO coefficients at telecommunication wavelengths. For instance, the EO polymer AJL8/APC (AJL8: nonlinear optical chromophore, and APC: amorphous polycarbonate has recently been incorporated into waveguide modulators and achieved good performance for optical modulation. Finally, very low loss transparent conducting oxide (TCO) electrodes have drawn increasing attention for applications in optoelectronic devices. Here we will address how the low loss indium oxide (In₂O₃) electrodes with an absorption coefficient ~1000/cm and conductivity ~204 S/cm can help improve the modulation performance of EO polymer Fabry-Pérot étalons using the advanced electro-optic (EO) polymer material (AJL8/APC). A hybrid etalon structure with one highly conductive indium tin oxide (ITO) electrode outside the etalon cavity and one low-absorption In₂O₃ electrode inside etalon cavity has been demonstrated. High finesse (~234), improved effective applied voltage ratio (~0.25), and low insertion loss (~4 dB) have been obtained. A 10 dB isolation ratio and ~10% modulation depth at 200 kHz with only 5 V applied voltage have been achieved. These results indicate that such etalons are very promising candidates for ultrafast spatial light modulation in information technology.

A thermally stable crosslinkable electro-optic (EO) polymer is successfully contact-poled in a hybrid EO polymer/sol-gel waveguide modulator. The highest EO coefficient is demonstrated when the EO polymer is poled with a low resistivity sol-gel cladding layer. We achieve the highest in-device EO polymer r₃₃ coefficient of 170pm/V at 1.55&mgr;m, which has not been possible with previously reported polymer claddings. A sol-gel waveguide/cladding plays the main role in our hybrid approach not only for poling efficiency, but also for low coupling loss, and stable coupling and waveguiding. The coupled light from the optical fiber propagates through the sol-gel input waveguide and adiabatically vertically transits between the sol-gel core and the EO polymer core. A phase modulator and a Mach-Zehnder modulator with a 2.4cm-long electrode and an inter-electrode distance of 15&mgr;m demonstrated a half wave voltages (V _&pgr;) of 2.5V and 1.0V at 1.55&mgr;m, respectively. We also examine a push-pull poled Mach-Zehnder waveguide modulator.

We have started the basic researches in order to investigate and explain the relation between photonics polymers and their properties. And based on them, we have proposed and demonstrated photonics polymers with new optical functions for application in photonics fields, for example, graded-index polymer optical fibers (GI-POFs), highly scattered optical transmission polymers, zero-birefringence optical polymers, and polymer optical fiber amplifiers and lasers. We propose the concept of "Fiber to the Display" and will apply these photonics polymers for it. In this concept, the GI-POF is directly connected to a large and high-quality display with more than gigabit order data transmission. Therefore, the real-time communication by high quality motion picture will become available for the first time even at home. The gigabit technology which we propose will bring us back to "Face-to-Face Communication".

We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

A novel fabrication method of graded index polymer optical fibers (GI-POFs) called the "co-extrusion process" is proposed and demonstrated for first time. This continuous fabrication process can reduce the fabrication cost of GI-POFs. Dopant diffusion temperature, dopant diffusion time, and the molecular weight of PMMA were optimized. By this optimization, desirable refractive index profile was achieved. Therefore, it is exhibited that the GI-POF obtained by the co-extrusion process has as high bandwidth as the one prepared by the conventional interfacial-gel polymerization process.

A chemical system consisting of a metallic salt, a water-soluble polymeric matrix and a photosensitive specie absorbing at two-photon, has been used to produce metal deposition upon exposure to a femtosecond laser. We show that this technique can be used to fabricate 2D and 3D metallic structures with gold and silver. We illustrate the potential use of this technique for the fabrication of optical diffractive structures and we report on the first observations of spectral filtering effects in the near vicinity of micro/nano structures.

We described a nonlinear optical metamaterial formed by randomly dispersing coated core-shell nano-spheres in aligned nematic liquid crystals. Such material will exhibit effective refractive indices ranging from negative, through zero to positive values. The nano-spheres dispersed liquid crystal possesses an effective birefringence that is larger than the natural birefringence of the host liquid crystal, which effectively enhances the nonlinear optical response associated with optical field induced director axis reorientation.

We study a new series of asymmetrical phthalocyanines with promising properties for two-photon 3D optical memory. The chromophores have a strong and narrow one-photon absorption (1PA) S₀ -> S₁ band at 730-760 nm, with a 200-400 cm^-1 width. Tuning the laser frequency 500-1000 cm^-1 below the S₀ -> S₁ band allows for very high values of two-photon absorption (2PA) cross-section &sgr;2 > 10⁴ GM. At temperatures T < 110K the molecules can be switched between two tautomer forms by 2PA. We measure 2PA spectra as a function of frequency and sample temperature. We provide an analysis of changes in 2PA spectra and cross sections due to different substituent groups. As a result, we found that among the set of studied molecules, there is one which is the most promising for rewritable 3D optical memory.

A selection rule for two-photon transition is considered based on the alternancy symmetry and the result is adopted to explain the experimental and calculation results of two-photon absorption (TPA) properties of two diacetylene derivatives with neutral and charged peripheral groups. The discussion successfully explains the difference in strength of the TPA bands and the existence of the higher-lying TPA states that is strongly allowed and plays a main role to the resonance enhancement of TPA.

A group of organic chromophoric molecules including siloles, pyrans, tetraphenylethylenes and fulvenes, are designed and synthesized. Light emissions of conventional luminescent materials are often quenched by aggregate formation. These molecules, however, become stronger luminophors when aggregated although they are practically nonemissive in their dilute solutions. By varying their packing structures in the aggregation states, emission color ranging from blue to red can be achieved. The emission of fulvenes can also be controlled by changing their morphology. While they emit a faint light in the amorphous state, their crystal forms are strongly luminescent. Intermolecular interaction or restriction of intramolecular rotation in different states may be responsible for such behaviors. Thanks to such effects, the molecules can be employed as sensors for the detection of explosives, organic solvent vapors, solution pH, and biomacromolecules. Further modification of their structures by molecular engineering endeavors may generate materials that can find an array of applications in optical display systems and as biological probes.

Organic thin films which are based on Van der Waals-bonded molecular organic compounds can be deposited onto a variety of substrates including scanning probe cantilevers without the lattice-matching constraints of conventional covalently-bonded semiconductors. Here we demonstrate organic light-emitting devices (OLEDs) fabricated on scanning probe cantilevers using thermal evaporation of molecular organic compounds and metallic electrodes. Ion beam lithography was used to define the emissive region in the shape of a ring having a diameter of 5 micrometers. The width of the ring emission was less than a micron as measured in the far field. Stable light emission was observed from the device at forward bias, with a current-voltage response similar to that of archetypal OLEDs. Such a probe can enable a new form of electrically-pumped SNOM compatible with existing atomic force microscopy tools and techniques. The emission wavelength can be tuned across the entire visible spectrum, including white light emission, by altering the composition of the emissive layer with a wide range of luminescent dyes. Should the ring-shaped light emission be used for imaging, the sample image can be deconvolved using a ring filter to achieve high resolution. The OLED probe can also be used to transfer excitons through the cathode to a sample via plasmon-assisted energy transfer; such a probe would be valuable for studying exciton dynamics in organic or organic/inorganic hybrid photovoltaic devices. By demonstrating the first active organic device on a scanning probe cantilever, this work opens the door to a wide range of new scanning probe techniques based on this class of materials for areas such as biological imaging.

Organic solid thin films of PMMA and surfactant-treated salmon deoxyribonucleic acid (DNA) were used as host materials to dope sulforhodamine (SRh) laser dye. Amplified Spontaneous Emission (ASE) was observed from the dye-doped thin films pumped by frequency-doubled Nd:YAG laser, with DNA host showed a lower ASE pump threshold. Distributed feedback (DFB) laser structures were fabricated on both dye-doped thin films for the 2^nd order emission of SRh at 650 nm. Stimulated Emission (Lasing) was obtained by pumping with a doubled Nd:YAG laser at 532 nm. The DNA DFB devices lasing threshold was 30&mgr;J/cm² or 3.75kW/cm². The emission linewidth decreased from ~ 30 nm in the ASE mode to < 0.4 nm in the lasing mode. The slope efficiency of the laser emission was ~ 1.2%. Similar emission linewidth change was observed in PMMA DFB devices while the lasing threshold was 53 &mgr;J/cm² or 6.63kW/cm² with a slope efficiency of ~0.63%.

Conductive polymers have become an extremely useful class of materials for many optical applications. Additionally, advanced fabrication methods have led to the development of metal based micro-wiregrid polarizers utilizing submicron features. Adapting these fabrication approaches for use with polymer materials leads to optical polarizers with unique properties. The patterning of conductive polymers with the small features required for wiregrid polarizers leads to several challenges. First, the deposition of the polymer must provide a layer thick enough to provide a polarizer with a useful extinction ratio that also has high conductivity and environmental stability. Two deposition approaches have been investigated, spin coating and electrochemical growth, and results of this work will be presented. Also, the polymers considered here are not compatible with basic photoresist processes. Various tactics have been examined to overcome this difficulty including the use of hard bakes of the polymer, protective overcoats and patterned growth. The adaptations required for successfully patterning the polymer will be reviewed. Finally, fabricated devices will be shown and their optical characterization presented.

Photobleaching was used for the fabrication of electro-optic polymer microrings resonators. All the device parameters were theoretically optimized. The photobleaching mask was made using e-beam lithography. UV exposure through the mask defined the pattern in the polymer by an irreversible change of the material properties and decrease of the refractive index. Waveguide coupled microring resonators have shown 15 dB resonance contrast and low total insertion loss of 9 dB, most of which was mainly due to fiber coupling in and out of the chip.

The optically induced switching of material properties is important for investigations of opto-electronic effects and optomechanical properties. Investigated organic materials contain chromophore dipole consisting of acceptor and donor groups bridged by a delocalized &pgr;-electron system. Both calculations and experimental data show a reversible highly dipolar photoinduced intra molecular charge transfer in indandione type molecules (DMABI) accompanied by change of the sign and the value of the dipole moment. Investigations of optical properties of thin host-guest polymer films show that the photoinduced process of DMABI is related to the photoinduced switching between two equally stable states of the molecule. In this work first results of formation of the surface relief in polymer films incorporated with DMABI derivatives will be presented. The refractive index gratings of DMABI host-guest films show that red light is less diffracted than blue one. The reversible surface potential changes on irradiation in photoinduced intramolecular electron transfer band in polymer host-guest films is observed. The DMABI molecules in solid state have nonlinear optical properties, which can be used and investigated in host-guest polymer matrix. The influence of concentration of DMABI molecules on photoinduced processes is discussed.

We synthesized a photoluminescent conductor polymer composed of polyvinyl alcohol, which was doped with nickel chloride to decrease its resistivity (300 Ωcm) and benzalkonium chloride to obtain photoluminescence properties, when it is radiated with a green laser beam (532 nm). We compared its absorbance curve and its energy emitted curve to observe the amount energy that is taken advantage of this process. Besides we research the photoluminescence behavior when an electric currant is applied in our conductor polymer, obtaining a modulation capacity.

Photoluminescence light is emitted at 640 nm by a biopolymeric emulsion based on glucose and current colorant when it is radiated by a green laser at 532nm. Its absorbance profile behavior versus its photoluminescence spectra was graphed and compared, also the photoluminescence emission was compared with the pumping profile which was modulated with a chopper at 140 hertz to obtain the same modulation of its photoluminescent emission. Thus it was distinguished and analyzed the phenomenon behavior.

In this work, the emission efficiency and spectral shift with respect to viewing angle were optimized by optimizing the design of the multi-layer top mirror of a microcavity OLED device. We first established criteria for the emission side mirror in order to optimize light intensity and spectral shift with viewing angle. Then we designed mirror using metallic and dielectric layers based on the target defined. The electroluminescence emission spectra of a microcavity OLED consisting of widely used organic materials, N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine (NPB) as a hole transport layer and tris (8-hydroxyquinoline) (Alq₃) as emitting and electron transporting layer was then calculated. Silver was used as the anode and back reflection mirror for the microcavity OLED. The simulation was performed for both the conventional LiF/Al cathode/top mirror and the optimized 5-layered top mirror. Our results indicate that by following the design procedure outlined, we simultaneously optimize the device for better light intensity and spectral shift with viewing angle.