PHOTOREFRACTIVITY IN A NOVEL POLYMER COMPOSITE WITH HIGH DIFFRACTION EFFICIENCY AND BROAD OPTICAL TRANSPARENCY

A novel photorefractive polymer composite has been developed in which a new organic dye, 4-[N-(2-hydroxyethyl)-N-methylamino] -4'-[(6-hydrox yhexyl)sulfonyl] stilbene, is used as a second-order nonlinear optical chromophore together with poly(N-vinylcarbazole) as the hole-transpor ting matrix, tricresyl phosphate as a plasticizer, and C-60 as a photo sensitizer. The photoconductive, electro-optic, and photorefractive pr operties of the material have been experimentally studied at wavelengt hs of 488, 514.5, and 632.8 nm. The amplitude and the phase dependenci es of the electro-optic response have been investigated. The composite shows high photorefractivity over a broad wavelength range. Diffracti on efficiencies between 20% and 40% as well as net two-beam coupling g ains of 25-65 cm(-1) have been obtained at wavelengths of 488, 514.5, and 632.8 nm.