Optical parametric oscillation in quasi-phase-matched GaAs

We demonstrate an optical parametric oscillator (OPO) based on GaAs. The OPO utilizes an all-epitaxially-grown orientation-patterned GaAs crystal that is 0.5 mm thick, 5 mm wide, and 11 mm long, with a domain reversal period of 61.2µm . Tuning either the near-IR pump wavelength between 1.8 and 2µm or the temperature of the GaAs crystal allows the mid-IR output to be tuned between 2.28 and 9.14µm , which is limited only by the spectral range of the OPO mirrors. The pump threshold of the singly resonant OPO is 16µJ for the 6-ns pump pulses, and the photon conversion slope efficiency reaches 54%. We also show experimentally the possibility of pump-polarization-independent frequency conversion in GaAs.