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.