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

Abstract

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 Cleartran™ 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.