Determination of optimal conditions for wavefront phase conjugation in a photorefractive crystal of the 4¯3m symmetry class

Subject of study. Wavefront conjugation during the diffraction of optical radiation by phase–amplitude holographic gratings in a cubic photorefractive crystal of the 4¯3m symmetry class is studied. Aim of study . The aim of the study is to determine the optimal conditions for four-wave mixing (FWM), under which the maximum intensity of the phase-conjugated wave is achieved, in a photorefractive crystal of 4¯3m symmetry class. Method . Numerical solutions of coupled wave equations are determined while taking into account the contributions of linear electro-optic, photoelastic, and inverse piezoelectric effects, as well as the linear absorption of the crystal. Main results . Under optimal conditions, the FWM reflectivity achieved in a semiconductor with GaAs parameters for the (111) crystal cut is higher than that for the (110) and (001) cuts. For a given linear absorption coefficient, local maxima of the reflectivity are obtained for a crystal thickness of approximately 20 mm. For each crystal cut, we determine the crystal orientation angle and azimuths of the linearly polarized optical beams at which the intensity of the phase-conjugated wave maximizes. Practical significance . This study demonstrates that the efficiency of optical beam diffraction by holographic gratings in a GaAs semiconductor can be increased by selecting optimal crystal and holographic setup parameters.