Yb-fiber-pumped, high-beam-quality, idler-resonant mid-infrared picosecond optical parametric oscillator

We report an Yb-fiber-pumped picosecond optical parametric oscillator (OPO) delivering high average power in excellent beam quality throughout the mid-infrared (mid-IR). Using MgO:PPLN as the nonlinear crystal and configured as a singly-resonant oscillator in the mid-IR idler wave. the OPO provides up to 3.5 W average power in high spatial quality with M-2<1.8 across a continuous tuning range of 4028-2198 nm, with M-2 <1.5 at 4000 mu. It can also deliver as much as 4.3 W of signal power in an output beam with M-2/<1.4 across 1446-2062 nm. The extracted idler exhibits a passive power stability better than 0.46% rms over 1 hour across the entire mid-IR tuning range. We have also investigated OPO cavity length detuning behavior about the zero-group-velocity-mismatch crossing point and its effects on output power. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement