New far-infrared transmitting Te-based chalcogenide glasses

This study reports on the synthesis of tellurium-based glasses that have a wide transmission far beyond the second atmospheric window. Several far-infrared(IR) transmitting glass systems including Ge-In-Te, Ge-Ga-Te, as well as some compositions containing alkali halides (KI, CsI) or metal halides (PbI2, CuI, AgI, CdI2 or ZnI2) are reported. Their glass-forming ability, thermal stability, and IR transmitting property are investigated. The results show that the broad absorption peak in the 15–20 μm disappear in the Fourier-transform infrared (spectrometer) spectra when gallium is replaced by indium. Te-based chalcogenide glasses containing metal-halides show superior glass-forming ability and better thermal stability than those containing alkali halides. Among these glasses, the ΔT of glass composition 65GeTe4-17In2Te6-18AgI can be as great as 115 °C. In ternary system, the glass composition Ge16Te69(AgI)15 (ΔT = 120 °C) is stable enough toward crystallization in combination with broad transmission region ...