HIGH-GAIN NONDEGENERATE 2-WAVE MIXING IN CR-YALO3

A gain of 22 times was obtained by nondegenerate two-wave mixing in Cr :YAlO3. To our knowledge, this is the largest cw two-wave mixing gain obtained in a hulk solid-state nonphotorefractive material. The measur ed gain appears to be limited by beam breakup that is due to spatial n onuniformities in the nonlinear refractive-index change that are the r esult of inhomogeneities in the crystal. Predictions based on our data indicate that gain in excess of 200 times should be possible in Cr:YA lO3 if a homogeneous crystal can be obtained.