A 22-watt mid-infrared optical parametric oscillator with V-shaped 3-mirror ring resonator.

Abstract
We report on a ZnGeP2-based optical parametric oscillator (OPO) with 22 W of output power in the 3-5 µm range and a beam quality factor M2 ≈1.4. The OPO uses a novel V-shaped 3-mirror ring resonator that allows two passes of the beams through the same nonlinear crystal. The pump is a 39 W hybrid Tm:fiber laser/Ho:YAG laser.