<title>Long-wavelength infrared transmitting glasses: new ternary sulfide compositions</title>

Abstract

Compositions in the MS-In₂S₃ and MS-Y₂S₃ systems (M equals Ca or Sr) have been investigated as potential long-wavelength infrared transmitting materials with possible glass-formability. Previous studies of CaY₂S₄ and SrY₂S₄ single crystals show that these phases have intrinsic infrared cut-offs at longer wavelengths than ZnS, however phases in these systems often exhibit poor crystallinity. Preliminary results indicate that these materials are significantly harder than ZnS, however, they are extremely refractory and therefore difficult to melt by traditional methods.