2k-Grating-assisted self-pumped phase conjugation: Theoretical and experimental studies

We investigated 2k-grating-assisted self-pumped phase conjugation in photorefractive Ce:BaTiO₃ crystals. The phase-conjugation process involves a combination of four-wave mixing and stimulated photorefractive backscattering. An approximation involving separate interaction regions is used to theoretically calculate the reflectivity of phase conjugation as a function of the coupling strength of four-wave mixing and stimulated photorefractive backscattering. In our experiments, grating-erasure techniques are employed at the interaction regions to investigate the dependence of phase-conjugate reflectivity on the coupling strength of four-wave mixing and stimulated photorefractive backscattering. The experimental results are in good agreement with the theoretical prediction.