Watt-Level Continuous-Wave Single-Frequency Mid-Infrared Optical Parametric Oscillator Based on MgO:PPLN at 3.68 µm

We report a continuous-wave single-frequency singly-resonant mid-infrared optical parametric oscillator (OPO). The OPO is based on 5 mol % MgO-doped periodically poled lithium niobate (MgO:PPLN) pumped by a continuous-wave single-frequency Nd:YVO4 laser at 1064 nm. A four-mirror bow-tie ring cavity configuration is adopted. A low-finesse intracavity etalon is utilized to compress the linewidth of the resonant signal. A single-frequency idler output power higher than 1 W at 3.68 µm is obtained.