Glass formation and optical properties of Sn modified GeS 2 -Ga 2 S 3 -CsCl chalcogenide glasses

Chalcogenide glass is emerging as important IR materials for advanced athermal infrared (IR) optical systems because of its low thermal coefficient of refractive index. New chalcogenide glasses based on 75GeS 2 -15Ga 2 S 3 -10CsCl were developed through the substitution of GeS 2 by SnS 2. The introduction of heavier tin (Sn) results in the red shift of transmission window, both of visible and long-wavelength IR cut-off edges, the elevation of refractive index dispersion curves, and the decreasing of glass transition temperature. The formation of [SnS 4-x Cl x ] structural units, instead of [GeS 4-x Cl x ], should be responsible for the variation of these structural properties. In addition, homogeneous Sn modified GeS 2 -Ga 2 S 3 -CsCl chalcogenide glass of Φ30 mm was also prepared successfully, showing it of high potential for commercial applications.