SPATIAL SHIFTS OF THE CONJUGATE BEAM GENERATED BY A NONDEGENERATE PHOTOREFRACTIVE PHASE-CONJUGATE MIRROR

We, demonstrate that the phase conjugation of a beam during nondegener ate four-wave mixing is accompanied by a spatial shift relative to the degenerate conjugate-beam location. Experiments with a photorefractiv e phase-conjugate mirror reveal that the phase-conjugate beam shifts h ave a nonmonotonic dependence on the probe's detuning frequency and co mprise both lateral displacements of up to 218 mu m and angular tilts of up to 34 are sec. An approximate theory based on spatial dispersion coefficients is in partial agreement with the experimental results. ( C) 1998 Optical Society of America OCIS codes: 190.5040, 190.4380, 190 .5330, 190.4420.