Beam Quality Enhancement in High Power mid-IR ZGP OPO Sources: a Focus on Thermal Lens Build-up

We reached an optical output power up to 38 W (M2 < 2) in 3 − 5 µm range from a ZGP OPO pumped by a 68 W 10 kHz Ho:LLF MOPA system. We report methods for improvement of beam quality at such power levels and present time-resolved studies of thermal lens.