Highly efficient diffraction in photorefractive BSO-BGO crystals at large applied fields

Abstract
The photoconductive and photorefractive properties of three undoped sellenite crystals (Bi12SiO20- Bi12GeO20) are investigated. We report, high grating diffraction efficiencies (nS ≃ 95%) when large electric fields are applied to low photoconductive crystals (E0 = 12kVcm-1) and nearly complete beam depletion in two wave mixing witli moving grating (grating period A = 20 μm).