Backward-wave medium infra-red down-conversion in proustite

Abstract

Phase-matched backward-wave down-conversion has been obtained in the medium infrared using proustite (Ag3AsS3) as the mixing crystal. A transmission window between the two-photon lattice band and the high-frequency wing of the reststrahlen permitted 18.6 µm infrared to be generated by mixing the output of a ruby laser with stimulated Raman emission from bromoform (CHBr3)