Optical nonlinearity of some stannite and famatinite crystals

Ternary chalcopyrite crystals are well studied and some of the promising crystals are finding useful applications in nonlinear optical devices. Two other groups of diamond-like crystals are considered: stannite and famatinite which are derived from chalcopyrite. Nonlinearity and average refractive index are calculated for some non-cubic members of these crystal groups by extension of Levine's theory. The purpose is to throw light to such unstudied crystal groups for their possible use in infrared nonlinear optics. Some of these crystals exhibit high optical nonlinearity and so could be promising for nonlinear optics.