Ternary and quaternary selenide crystals for nonlinear optical applications

We have developed several binary, ternary and quaternary sulfide and selenide crystals for nonlinear optical applications and present an overview on the crystal growth and characterization of crystals for nonlinear optical (NLO) conversion efficiency. We have summarized the performance of silver gallium selenide (AgGaSe2), thallium arsenic selenide (Tl3AsSe3), and silver gallium germanium selenide (AgGaGe3Se8 and AgGaGe5Se12) crystals and have compared with gallium selenide (GaSe). All these crystals were grown by vertical Bridgman method in quartz ampoules by using stoichiometric compounds synthesized from constituent elements. The significant problem of cleaving of GaSe was reduced in ternary and quaternary compounds. Experimental results showed that binary, ternary and quaternary selenide compounds transmit at wavelengths up to 16 μm, have reasonably high value of nonlinear conversion merit (d2/n3, where d is the NLO coefficient and n is the refractive index) and have the lowest absorption coefficient compared to arsenides, phosphides and other nonlinear optical (NLO) materials.