Recent advances in photorefractive polymer materials

This paper summarizes current research to develop photorefractive polymeric materials with improved speed, material stability, and high beam coupling gain. The recent demonstration of significantly improved two-beam coupling marks the entry into a gain regime which enables the observation of new effects for the first time, such as beam fanning and self-pumped phase-conjugation. These effects have previously been observed only in a few thick high gain inorganic photorefractive crystals. The large beam coupling forces the reinterpretation of such traditional characterization techniques such as the grating translation method for the determination of the spatial phase of the index grating. Our subsequent material study focuses on several compositional variations to investigate the effect on the photorefractive performance of varying the chromophore and charge transporting polymer.