Materials demonstrating a photorefractive effect are principal candidates for numerous applications, including high-density optical data storage, optical image processing, phase conjugated mirrors and lasers, dynamic holography, optical computing, pattern recognition, etc. Considerable progress has been made in the research on photorefractive polymers and composite materials in the last few years. These materials have many advantages over inorganic photorefractive crystals, including large optical nonlinearities, low dielectric constants, low cost and ease of fabrication. A large number of materials, including those exhibiting an extremely large photorefractive effect, have been developed. In addition, a number of interesting phenomena particular to polymeric photorefractive materials have been reported and corresponding mechanisms have been proposed to account for these phenomena. Possible applications of these materials have been explored with the demonstration of a volume holographic storage device based on photorefractive polymers. This paper reviews the latest developments of the young and exciting field of polymeric photorefractive materials.

We report the synthesis and characterization of a new, low-T, polymer exhibiting the photorefractive effect. The photorefractive polymer contains a second-order nonlinear optical chromophore, a charge transporting group, and a long aliphatic chain covalently linked to the polymer backbone. A sensitizer (CSO) was molecularly doped into the polymer to facilitate photocharge generation. The photoconductivity, electrooptic (Pockels) effect, and photorefractive properties of the polymer are reported.

We present electroluminescent (EL) properties of new blue-green organic dyes. The molecular structures of these dyes are based on 2,7-divinyl-9,9-bis(tert-butyl)fluorene, a π-electron bridge, end-capped with electron donor (D) and/or electron acceptor (A) group(s) to form D-π-A, D-π-D, and A-π-A structures. The donor group is a triphenylamine, and the acceptor group is a diphenyloxadiazole. We studied EL properties of these dyes in a single-layer EL device having the following structure: ITO/PVK:DYE/Ca/Al. We found that both the wavelength of maximum emission and the threshold of EL depend on the structure and the concentration of the dye. Among the structure reported here, the D-π-A dye shows the highest EL performance, exhibiting a brightness of 498 cd/m 2 at an applied voltage of 25 V.

A bifunctional chromophore has been developed which serves as a charge transporting agent as well as a second-order nonlinear optical compound. The chromophore has been incorporated into an inert polymer to form a photorefractive material when doped with a photocharge generation sensitizer. The dependence of the four-wave mixing diffraction efficiency, holographic grating writing rate, and two-beam coupling gain on the chromophore concentration has been studied. The results confirm the photorefractive character of the composite.