Efficient parametric generators of picosecond mid-infrared pulses based on AgGaS2 crystals

An investigation was made of parametric oscillation in silver thiogallate (AgGaS₂) crystals pumped by single picosecond pulses from an Nd:YAG laser (λ = 1.064 μm). This resulted in generation of 2.2 — 7.4 μm radiation. The conversion efficiency achieved in a noncollinear two-crystal configuration was considerably higher than that reached earlier for picosecond parametric oscillators in the same spectral range. A variant of a two-pass oscillator with a single crystal was constructed and found to have some advantages compared with a two-crystal oscillator.