High Power Conversion to Mid-IR Using KTP and ZGP OPOs*

A high average power, OPO based system has been developed for the purpose of generating output in the 2 - 5 µm mid-IR band. The system uses a cw diode array - pumped, Nd:YAG master oscillator power amplifier (MOPA) as the pump source and two tandem OPOs for wavelength conversion to the mid-IR. A Type II degenerate KTP OPO was used to convert the pump beam to 2.13 µm and a Type I near degenerate zinc germanium phosphite (ZGP) OPO was used to generate broadband radiation in the 3.7 - 4.1 and 4.4 - 4.8 µm wavelength range.