PHASE-MATCHED UP CONVERSION OF 10.6-μ RADIATION IN ZnGeP2

Abstract
Phase‐matched sum mixing of 10.6‐ and 1.06‐μ radiation has been observed at near normal to the optic axis in ZnGeP2. Its theoretical performance as a 10.6‐μ detector via up conversion compares favorably with direct detection by a cooled Ge:Hg photoconductive detector. The sum‐mixing efficiency of ZnGeP2 is 140 times superior to that of Ag3AsS3, the next best material. The large angular aperture resulting from θ m ≃ 90° indicates that the material will be useful for image up conversion.