EFFECT OF BEAM COHERENCE ON MUTUALLY PUMPED PHASE CONJUGATORS

The performance of four different mutually pumped phase conjugators in barium titanate depends on the mutual coherence of the two input beam s. In three of the conjugators the use of fully mutually coherent inpu t beams enhances the overall phase-conjugate reflectivity. We find tha t backscattering and transmission gratings in the photorefractive crys tal both contribute to the phase-conjugate signal and that their relat ive strength depends on the relative coherence of the two input beams. We numerically solve coupled-wave equations that include all gratings and find reasonable agreement between our theory and our experimental data.