Over 20-W Mid-Infrared Picosecond Optical Parametric Oscillator

We report on a high-average-power mid-infrared picosecond optical parametric oscillator (OPO) synchronously pumped by a Nd:YVO
₄
mode-locked laser. By use of the MgO-doped periodically poled LiNbO
₃
as the nonlinear crystal, up to 20.2-W picosecond laser at 2128 nm was generated from the degenerate OPO, with a conversion efficiency of 66%. To the best of our knowledge, this is the highest mid-infrared average output power from synchronously pumped OPO so far. The output picosecond laser had a pulse duration of 29 ps and a pulse energy of 196 nJ, with an M
²
beam quality factor of 1.5. In the nondegenerate state operation, the signal power of 12.8 W at 1966 nm and the idler power of 10.5 W at 2319 nm were obtained, with a conversion efficiency as high as 76%. The high-average-power mid-infrared picosecond OPO may lead to the application of medical surgery, microprocessing of materials, etc.