Abstract

A group of chalcopyrite semiconductors such as AgGaSe₂, AgGaS₂, and CdGeAs₂ crystals are the only promising candidates for second-harmonic generation (SHG) in the mid-infrared.^1,2 The AgCaSe₂ crystal has not only large nonlinear optical (NLO) susceptibility among these crystals, but also is transparent over the wavelengths ranging from 0.75–17 µm. Thus far, SHG has been observed by using this crystal with a pulsed CO₂ laser in an extracavity scheme.³ However, no work has been reported with an intracavity setting in continuous-wave (cw) operation. In this paper we report SHG of cw CO₂ laser lines with intracavity-set AgGaSe₂ crystal, aiming for a simple-probe laser to CO laser study.

© 1992 Optical Society of America