Double phase-conjugate mirror : experimental investigation and comparison with theory

An experimental investigation of the geometry of a double phase-conjugate mirror in a photorefractive strontium barium niobate crystal is carried out. A shift of the transverse intensity distributions of scattered beams with respect to those of pump beams and a sublinear dependence of the scattered-beam power ratio on the power ratio of the pump beams are observed. The experimental results are interpreted on the basis of a two-dimensional model that accounts for both four-wave mixing and fanning.