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 demonstrated for the first time to our knowledge. An experimental phase-conjugate energy reflectivity of similar to 2% and an overall efficiency of similar to 0.4% are achieved. Because of the presence of absorbing dipoles oriented along specific directions, it is shown that the phase-conjugated beam can be made orthogonally polarized relative to the signal beam or to both pump beams with almost no reduction of the energy reflectivity. (C) 1996 Optical Society of America