High-repetition-rate, deep-infrared, picosecond optical parametric oscillator based on CdSiP₂

We report a high-repetition-rate picosecond optical parametric oscillator (OPO) based on CdSiP₂ (CSP) that is synchronously pumped by an Yb-fiber laser at 1064 nm and provides high average power in the deep-infrared (deep-IR) at 79.5 MHz. The OPO is tunable across 6205-6710 nm in the idler, providing as much as 105 mW of average power at 6205 nm and >55  mW over nearly the entire tuning range. The deep-IR idler output exhibits passive power stability better than 2.3% rms over 12 h in good beam quality. The near-IR signal pulses from the OPO have a Gaussian pulse duration of ∼19  ps, measured at 1284 nm. We have investigated the temperature tuning characteristics of the OPO and compared the data with the theoretical calculations using the most recent Sellmeier equations and thermo-optic coefficients for the crystal. To the best of our knowledge, this is the first picosecond OPO based on CSP operating at MHz repetition rates.