Photorefractive two-beam coupling with applied radio-frequency fields: theory and experiment

Abstract
An expression for the gain in photorefractive two-wave mixing when radio-frequency (rf) electric fields are applied to the material has been derived and compared with experiments in GaAs:Cr. A fit to the data yields a consistent value for the carrier diffusion length of 0.3 μm. The rf field method can be used to enhance the two-wave mixing gain and to measure the diffusion length in other photorefractive materials.