Nanosecond optical parametric oscillator with midinfrared intracavity difference-frequency mixing in...

We report on efficient midinfrared difference-frequency generation (DFG) in orientation-patterned GaAs by intracavity mixing the signal and idler pulses of a narrowband nanosecond optical parametric oscillator based on periodically poled LiNbO₃. The maximum average DFG output power reached 215 mW at 8.15 µm for a repetition rate of 35 kHz. The temperature tuning range spanned over 8026-8710 nm. The maximum overall conversion efficiency from 1 to 8 µm amounted to ∼1.3%.