Photorefractive materials can form "instant" holograms without time-consuming development steps. Their potential applications include image processing, optical data storage, and correction of image distortion, but the cost of crystal growth and preparation has been a primary impediment to commercial application. Polymers, on the other hand, are low in cost and readily fabricated in a variety of forms. Photorefractive polymers were constructed with performance that matched or exceeded the performance of available photorefractive crystals. The largest observed two-beam energy coupling gain coefficient for the polymers was 56 per centimeter.

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We report the photoconductive properties and photorefractive grating response time of a polymer mixture composed of 40-wt. % dissolved diethylamino-benzaldehyde diphenyl hydrazone (DEH) and the non-cross-linking epoxy polymer Bisphenol A 4,4'-nitroaminostilbene. The films have improved photoconductive sensitivities as high as 2.1 x 10-1o cm/(W fi) at a wavelength of 650 nm with a corresponding reduction of the grating response time constant to 0.11 ± 0.02 s at an intensity of 1 W/cm 2 . The nitro-aminostilbene chromophore is deduced to be the source of photogenerated charge carriers on the basis of a comparison of the wavelength dependence of the photoconductivity and absorption coefficient. Degradation of the photoconductivity and the dark conductivity as well as of the photorefractive speed with sample age is attributed to precipitation of the DEH; this explanation is supported by x-ray diffraction observations of crystal growth in the polymer.

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The polymer Bisphenol A 4,4'-nitroaminostilbene mixed with 40 wt. % benzaldehyde-diphenyl hydrazone is typical of the epoxy-based photorefractive polymers recently shown to be photorefractive.1