Theoretical and Experimental Studies of Photorefractivity in Novel Polymeric Composites

We present results of temperature dependence studies of photorefractive effect in a polymeric composite PVK:TCP:C 60:DEANST. At elevated temperature, decreased rigidity of the host matrix leading to increased orientational mobility of the second-order nonlinear chromophores results in enhanced photorefractive performance. Diffraction efficiency approaching 100% and enhanced two-beam coupling gain coefficients are reported. The influence of temperature on the speed of photorefractive response is measured and discussed. We also report on a novel photorefractive polymeric composite. A new chromophore, 4-[N-(2- hydroxyethyl)-N-(methyl)amino phenyl]-4\u27-(6-hydroxyhexyl sulfonyl)stilbene, abbreviated as APSS, possessing high transparency over a broad wavelength, is used together with a PVK:TCP:C 60 matrix. This composite shows high photorefractive figures of merit at 488, 514.5 and 632.8 nm. Diffraction efficiencies up to 40%, as well as net two-beam coupling gains of 60 cm -1 have been achieved at these wavelengths