Asymmetric Energy Transfer in Photorefractive Polymer Composites Under Non-Electric Field

We prepared photorefractive composites using poly(methyl methacrylate) (PMMA) as a host material doped with 3-[(4-Nitrophenyl)azo]-9H-carbazole-9-ethanol (NACzE) as an NLO chromophore. Photorefractive properties were characterized by means of a two beam coupling (2BC) and a degenerated four wave mixing (DFWM) methods performed at 632.8 nm and room temperature. We successfully observed asymmetric 2BC under non-electric field: photorefractive characteristics obtained are a net 2BC gain of 426 cm(-1) and a diffraction efficiency of 35%. We could also demonstrate its high performance by DFWM image processing experiment. In order to reduce the glass transition temperature T-g of photorefractive composites we selected poly(ethyl methacrylate) (PEMA) as a host material. Photorefractive properties obtained are a net 2BC gain of 398 cm(-1) and a diffraction efficiency of 40%.