Expanding the transmission window of visible-MWIR chalcogenide glasses by silicon nitride doping

Gallium Lanthanum sulphur-oxide (GLSO) glass is an excellent candidate for a window/dome material ought to its wideband transmission window from visible to MWIR. The suitable optical transmission from 0.45-8 microns is supplemented by its superior thermal and mechanical properties to contemporary materials, such as CleartranT zinc sulphide. In this work, the properties of GLSO were enhanced by doping with small concentrations of silicon nitride (<= 0.5 M%), which expanded the transmission window to encompass all the visible spectra. Nano-indentation demonstrated that the hardness and elastic modulus slightly improved. Overall, the improvements demonstrated here make this glass an even better solution when compared to the state-of-the-art for use in single-optic windows and domes.