High efficiency and high peak power picosecond mid-infrared optical parametric amplifier based on BaGa4Se7 crystal.

A high efficiency and high peak power picosecond (ps) mid-infrared optical parametric amplifier with a new nonlinear crystal BaGa(4)Se(7) 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.