Continuous wavelength tuning from 39–12 µm from an optical parametric oscillator based on orientation-patterned GaP grown on GaAs

We report for the first time nonlinear frequency conversion—specifically optical parametric oscillation—in OP-GaP layers grown by hydride vapor-phase epitaxy on 3-inch OP-GaAs templates. Continuous tuning with wavelength coverage from 3.9–12 µm was achieved by using stepped and fan-out gratings having periods from 18.0–35.2 µm, which propagated 150 µm of a 1.2-mm-thick layer before overgrowth. Anti-reflection-coated OP-GaP crystals were pumped at 1040 nm with an ultrafast Yb-fiber laser, yielding idler output powers up to 150 mW (60 mW) in spectra centered at a wavelength of 5.6 µm (10.7 µm).