Accurate phase-matching conditions for AgGa1-xInxS2 mixed chalcopyrite crystals

This paper presents the Sellmeier equations for AgInS₂, combined with recently derived equations for AgGaS₂, to provide the accurate phase-matching conditions of AgGa_1−xIn_xS₂ for nonlinear three-wave mixing across the 0.6164–10.5910 µm range. A new set of these index formulas successfully reproduces the measured 90° phase-matching conditions of AgGa_0.46In_0.54S₂ (x=0.54) for frequency-doubling the emission of Nd:YAG laser-pumped optical parametric oscillators (OPOs) at 2.7780 and 8.6880 µm as well as for frequency-mixing the signal and idler outputs of such an OPO at 1.1940 and 9.7893 µm, respectively.