High‐energy optical parametric oscillator for the 6 μm spectral range based on HgGa2S4 pumped at 1064 nm

The defect chalcopyrite crystal HgGa₂S₄ has been employed in a 1064‐nm pumped optical parametric oscillator to generate <7 ns long idler pulses near 6.3 μm with energies as high as 3 mJ, tunable in a broad spectral range from 4.5 to 9 μm.