ABSTRACT:
To discover the signs of life on terrestrial planets, we must accurately detect the existence of CO2, which has two vibrational absorption bands at 4µm and 16 µm. Therefore optical materials be able to transmit light far beyond 20 µm are essential for manufacturing these detectors. 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 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 ?T of glass composition 65GeTe4-17In2Te6-18AgI can be as great as 115 degcel. In ternary system, the glass composition Ge16Te69(AgI)15 (?T=120 degcel) is stable enough toward crystallization in combination with broad transmission region and good chemical durability to be drawn into optical fibers.