PHASE-CONJUGATION IN CR4+ YAG AT 1.06-MU-M

Phase conjugation in a Cr4+:YAG saturable absorber by degenerate four- wave mixing with nanasecond pulses at lambda = 1.06 mu m is demonstrat ed for the first time to our knowledge. An experimental phase-conjugat e energy reflectivity of similar to 2% and an overall efficiency of si milar to 0.4% are achieved. Because of the presence of absorbing dipol es oriented along specific directions, it is shown that the phase-conj ugated beam can be made orthogonally polarized relative to the signal beam or to both pump beams with almost no reduction of the energy refl ectivity. (C) 1996 Optical Society of America