Photorefractive Polymers and Composites

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. Photorefractive materials have numerous potential applications in optical data processing. Recent advances in polymer and composite photorefractive materials are reviewed, including the various materials classes that have been developed and new phenomena that have been discovered. The figure shows an example of a bi‐functional chromophore that is used in photorefractive composite materials to reduce phase segregation.