Experimental investigation of vector phase conjugation in Nd(3+):YAG

We present a study of vector phase conjugation based on degenerate four-wave mixing in inverted Nd:YAG. The results demonstrate polarization correction for weak probe strength, with near-unity fidelity for polarization compensation of the returning conjugate. As the probe strength is increased, the fidelity of the polarization state of the conjugate is seen to deteriorate to an average value of 92% when the probe is strongly saturating and is several times stronger than the pump beams. We also show that, for strong probe strengths, an individual transmission grating or reflection grating is more efficient than when both gratings are present.