High-gain photorefractive reflection gratings in layered photoconductive polymers

Large two-wave mixing gain in reflection grating geometry is obtained in layered organic photorefractive polymers doped with the chromophore piperidinodicyanostyrene. With an applied field of 60 V/mum and for a grating spacing of 0.205 mum, one measures a two-wave mixing gain coefficient of 104 cm(-1) and a diffraction efficiency of 4.8% in 100-mum-thick samples. Our photorefractive and electrochemical investigations suggest that the excellent material performance in reflection grating geometry is associated with an increased effective number of trapping sites. (C) 2004 American Institute of Physics.