Holographic Bragg grating generation in photorefractive polymer-dissolved liquid-crystal composites

Abstract

A large optical nonlinearity of n2=0.57 cm2/W in photorefractive mesogenic composites was achieved with low applied dc fields (0.30 V/μm) and a fringe spacing of 2.8 μm. The resultant diffraction efficiency from the Bragg gratings, which were written by a less intense laser (frequency-doubled Nd-YAG laser with a 532 nm wavelength), was around 39%. The limiting factors underlying these nonlinearities and their dynamics are also discussed.