We have studied acceptor substituted poly(3-butyl)thiophene in an attempt to examine the role of acceptor molecules as intrinsic charge traps under light excitations by measuring the transient photoconductivity response following pulse excitation. The specially synthesized acceptor molecule is a chemically prepared high electron affinity (HEA) monomer, 1- (4-nitrophenyl)-2-(3-thienyl) ethene. In the co-polymers prepared with this acceptor monomer we have observed a simultaneous decrease of the sub-nanosecond photoconductivity and increase of the slow component is attributed to a bimolecular recombination process. A new photoinduced current rectifier based on an all-organic donor-acceptor bilayer substituted polythiophene derivative is described. Under visible and UV illumination, a p-n junction is formed leading to current rectification. Maximum photo-rectified current is obtained at approximately 400 nm, with a sharp decrease at shorter wavelengths. This sharp decrease indicates that photons with energy higher than 3.1 eV quench the light activation of this bilayer device.

Three new dodecahexayne compounds with urethane groups were synthesized and their solid-state polymerization was confirmed to be 1,4-addition to give octatetraynyl- substituted polydiacetylene (PDA) and partially to give a ladder polymer, in which two PDAs were bonded by butadiynylene groups. Though complete conversion to the ladder polymer was not observed, crystallinity of the polymer was preserved. This is due to hydrogen bonding between adjacent molecules or side chains. The (chi) ⁽³⁾ values of the polymerized spincoated films of the urethane- substituted dodecahexayne compounds were evaluated by the THG Maker fringe method. The largest value observed was 2.8 X 10^-11 esu for the polymer from 5BCMU-6A at 700 nm.

The excited state interactions occurring in a three- component system which can be used under visible laser light excitation and based on a derived dye thioxanthene derived dye TXD, an amine and an additive such as diphenyliodonium salt wee investigated through time-resolved absorption spectroscopy, spectrofluorometry and steady state photolysis. The rate constants of the various chemical processes taking place in the initiation step were measured. An overall photoinitiation mechanism is proposed. A sensitivity of 0.3 mJ cm^-2 obtained under laser scanning exposition is also reported.

Optical induction and study of convection in a thin film of dye doped nematic liquid crystal is reported. The temperature transverse gradient provided by the Gaussian beam profile makes possible the induction of convective motions of different regime in the nematic phase. These motions give rise to very large and non-uniform nonlinear phase modulation of the light, thus producing a corresponding far field intensity redistribution. The study of this distribution may provide important information about the convection in thin film liquids.

As a guest host system the poling behavior of the nonlinear dye in the polymer poly-(alpha) -methyl-styrene (P(alpha) MS) is investigated. The waveguides are studied as a part of a multilayer system on top of a ferroelectric buffer layer of P(VDF-TrFE). The orientational stability is measured on line by monitoring the waveguide anisotropy during poling and relaxation. The electric field depends on the layer thicknesses and the orientational stability strongly depends especially on the thickness of the ferroelectric buffer layer. At optimum conditions a permanent remanence of anisotropy oriented in the electrical field of the oriented ferroelectric buffer of about 60 percent is found. Thermal annealing of P(alpha) MS just below its glass transition temperature creates ferroelectricity in the P(alpha) MS matrix itself increasing orientational stability of the NLO dye to 75 percent.

The recent development of several organic materials with large nonlinear susceptibilities, high damage threshold and low melting points encouraged researchers to employ these materials in fiber form to efficiently couple diode laser pumps and obtain enhanced second harmonic generation (SHG). In this paper we report the growth of single crystal cored fibers of 4-nitro-4'-methylbenzylidene aniline, ethoxy methoxy chalcone and (-)2-((alpha) -methylbenzylamino)-5- nitropyridine by inverted Bridgman-Stockbarger technique. The fibers were grown in glass capillaries with varying internal diameters and lengths and were characterized using x-ray and polarizing microscope techniques. The propagation loss at 632.8 nm and 1300 nm were measured and SHG was studied using 1064 nm pump.

The successful synthesis of the LD-3 electrooptic polymer has resulted in a highly reliable nonlinear organic material. However, further progress has been impeded due to the fact that LD-3 films produced thus far are too thin to form useful waveguide devices. Here the formation of thick LD-3 films ranging from 1.2 micrometers to 2.4 micrometers by using cyclopentanone as the new solvent are reported. Preliminary waveguide loss studied shows a guide loss of approximately 3 dB/cm. Aimed at forming true-time-delay lines for phased- array antenna applications, optical heterodyne detection is conducted using various waveguide lengths. A heterodyne signal of a base bandwidth of 25 GHz is demonstrated with signal-to-noise ratio of 15 dB.

A new design for power splitters in transparent materials is presented. The common divider built with a cascade of Y- branches is replaced by a structure using the coupling of evanescent fields. This is demonstrated at the example of PMMA. It is structured using a photomask and UV-radiation in order to form the waveguides in the surface. The parameters of the material, especially the refractive index profile after UV-exposure, are fed into a computer simulation of the new design using beam propagation method software. The calculation leads to an optimum layout which is transformed to a photomask for the irradiation process. The theoretical as well as the experimental results are presented. A good agreement between calculation and measurement is obtained.

Samples of PMMA have been modified by ionizing radiation in order to generate regions of increased refractive index for the use as optical waveguides in a surface layer. To get a better understanding of the formation of these guides the chemical processes which are responsible for the increase of the refractive index were studied using different spectroscopic methods. It is shown that the thickness as well as the refractive index profile of the layer at the surface depends on the irradiation dose. In this paper also the guiding properties of the waveguides in dependence of these parameters are discussed. The waveguiding structures were used to build optical polarizers simply by varying the exposure time. The spectral absorption behavior of different strip waveguides for different exposure doses were studied.

Optical systems for parallel data processing and transmitting require multielement light beam devices. The paper discusses the HOE synthesis and manufacturing technology, as applied to problems of interconnects. The electron beam lithography is used to make HOE for the visible. HOEs operating at 630 and 530 nm have been made as various beamsplitters. The use of beamsplitters as auxiliary elements for making 3D holographic neural chips is considered. It can be done by successive recording of different splitters in a volume carrier, which can then be used for interconnects. Another method of interconnects makes use of an array of progammable bacteriorhodopsin microholograms for data flow switching in communication systems. The results of theoretical and experimental studies are given.

Angular multiplexed holograms in saturable organic media are theoretically investigated. An exposure schedule which produces uniform diffraction efficiency for multiplexed holograms is presented showing that the scheduling behavior changes dramatically when the light intensity changes. Unlike photorefractive materials, the resulting storage capacity depends on the light intensity and exposure time.

We report the study of azo-doped polymers using optical phase conjugation experiments in a degenerate four-wave mixing geometry using an argon ion laser at 488 nm. The photopolymer systems are constituted by PMMA films of 10 micrometers thick doped with novel push-pull azo-dyes. We have also performed real-time dynamic holography using these azo dye-doped PMMA systems. Coherent and non-coherent detection of the diffracted signal show complex holographic behavior of the systems as for the formation and erasure of the holograms. Light induced absorption in the red and near infrared band is observed and studied experimentally. Photophysical mechanisms are also discussed.

A novel TE-TM mode converter using optically active polymers (OAPs), which can be fabricated much more easily than the conventional ones, was proposed. To achieve its phase- matched operation, two methods for controlling birefringence in the OAP waveguides were studied and hence TE_o-TM_o mode conversion with a high efficiency of about 70 percent was obtained for the first time.

Grating formation in photoactive polymers are monitored by holographic recording. The photopolymers are based on acrylamide monomers, which are dissolved together with xanthine dyes in polyvinyl alcohol. Thin plastic coatings are obtained by casing on glass substrates. Photorecording occurs quasi-real-time and in-situ, meaning that no wet- chemical or post-thermal/photochemical processing is required. Formulations have been found, which produce large enough refractive index modulations, so that very high diffraction efficiencies can be obtained, when the recording beam angles are symmetric. Unfortunately, DEs significantly drop, when recording angles are highly asymmetric. The origin of this effect is shown to stem from grating anomalies, in that the slanted fringes bend due to nonlinear shrinkage effects during recording. The introduction of cross-linking and gelling agents stabilize the formed grating structures against dimensional distortions. These photopolymer layers have potential in photonics applications, such as holographic optical elements and waveguide structures.

Besides the advantage of acrylic glass as material for passive optical components (easy structure, acceptable loss, low cost) there is a limited stability against elevated temperatures and humidity. Therefore it is necessary to search for other polymers which avoid especially this disadvantage. Two new materials have been studied: poly- (methacryl-methyl-imide), a copolymer from Roehm Darmstadt consisting of methyl-methacrylate and imide with a glass transition temperature of more than 150 degrees C, depending on the imide concentration, and Benzenecylobutane, a material from Dow Chemical.First developed for coating material in electronics it exhibits excellent optical properties and a temperature stability of more than 350 degrees C. The obtained n_eff values as a function of ion energy, fluence and accumulated ion dose are reported.

Mathematical model of nonstationary holograms recording in photopolymer materials has been developed. Analytical solution has been found with variation of kinetic coefficients such as medium viscosity, diffusion coefficient, break reaction parameter of polymeric chain in polymerization being taken into account. Numerical results show the importance of these variations in kinetic holograms recording. Postexpositionary amplification of holograms in this model is described too.

The theoretical investigation of the problem of the nonstationary process of holograms reconstruction in photopolymer media has been carried out. Analytical solutions have been found and analyzed taking into account the radical polymerization process and diffusion processes of all components of photopolymer for symmetrical geometry of read out. The numerical results showing the kinetics of the hologram reconstruction, space-time transformation of the holographic gratings field, time evolution of the mismatch sensitivity of the dynamic holograms reconstruction are represented.

A new three-component photoinitiator system consisting of a dye, an iron arene complex and a phenylglycine derivative was investigated by fluorescence quenching experiments and time resolved absorption spectroscopy. The efficiency of this three-component system in photopolymerization reactions is higher by a two-fold factor compared to that of the two- component system dye/arene complex or dye/amine derivative. The first step of the photoreaction occurs between the dye and the iron arene complex, the latter reacts through an electron transfer reaction either with the singlet excited dye or with the triplet excited dye according to the nature of the sensitizing dye. The proposed mechanism for the higher efficiency of the three-component system involved the absence of terminating radical formation.

The study of double-exposure interferogram recording onto photothermoplastic media (PTPM) is carried out and the results are given. The peculiarities of surface relief development arising during the recording process with two charging cycles are determined. The practical recommendations are given to optimize the process of double-exposure interferogram recording onto PTPM.

Photopolymerizable systems were developed in Mulhouse as holographic recording materials. The direct generation of images with no post-treatment nor repositioning is their most attractive feature. Such media are ideally suited for real time interferometry. Compromises for definition of the exposure parameters were established, taking into account the desired diffraction efficiency and the exposure time that could not be lower than a few tenths of a second. On the other hand, the self-processing system was optimized for the recording of off-axis holographic lenses. With such a n end in view, the aim was not to attain the shortest and easiest handling time but the highest diffraction efficiency and the lowest optical noise. The diffracted beams were sharply focused and diffraction efficiencies higher than 80 percent were obtained at 514 nm. Since the chemical composition and the method of conditioning are very flexible, they can be adapted to meet the requirements for various applications.