COMMERCIALLY AVAILABLE HIGH QUALITY BIG SIZE NONLINEAR OPTICAL MATERIALS - AgGaS2, AgGaSe2 and HgGa2S4 nonlinear elements for conversion of the middle    infrared spectral range laser radiation. - AgGa1-xInxS2 and AgGa1-xInxSe2 nonlinear elements withvariable chemical    composition for non-critical phase matching processes over a wide wavelength    range.    Applications : Frequency mixing Frequency doubling Optical parametric sources    Advantages: High nonlinear susceptibility High damage threshold Wide transmission range Low optical absorption and scattering Low wave front distortion