Tunable near-infrared radiation by difference frequency mixing in beta barium borate crystal

Abstract
Noncollinear difference frequency mixing is reported for the first time in a barium borate crystal that generates near-infrared radiation tunable from 2.04 to 3.42 μm. The technique apart from verifying a very simple relation correlating the phase-matching angle with the noncollinear angle of the interacting beams provides a simple alternative scheme for generating coherent radiation in this important spectral range.