AGS is
transparent from 0.*3 to *2 µm. Although its nonlinear optical
coefficient is the lowest among the mentioned infrared
crystals, high short wavelength transparency edging at **0 nm is
made use of in OPOs pumped by Nd:YAG laser; in numerous difference
frequency mixing experiments with diode, Ti:Sapphire, Nd:YAG and IR
dye lasers covering 3–*2 µm range; in direct infrared
countermeasure systems, and for SHG of CO2 laser. Thin AgGaS2 (AGS)
crystal plates are popular for ultrashort pulse generation in mid
IR range by difference frequency generation employing NIR
wavelength pulses.
