High Efficiency and High Peak Power Picosecond Mid-Infrared Optical Parametric Amplifier Based on a New Crystal BaGa\u3csub\u3e4\u3c/sub\u3eSe\u3csub\u3e7\u3c/sub\u3e

A high efficiency and high peak power picosecond (ps) mid-infrared optical parametric amplifier with a new nonlinear crystal BaGa4Se7 pumped by a 30 ps 1064 nm Nd:YAG laser is demonstrated for the first time. The maximum photon conversion efficiency of 56% from 1064 nm to 3.9 μm idler has been achieved at the pump energy of ∼1.8 mJ. A maximum idler output of 830 μJ at 3.9 μm with peak power of ∼27 MW was obtained at pump energy of ∼9.1 mJ. Moreover, a 3–5 μm idler tuning range was demonstrated, with output energies of ∼300 μJ at 5 μm and up to 1 mJ at 3 μm at ∼8.2 mJ pump energy