Fluorescence of Erbium Dopant in CsCl-Ga-Ge-S glasses for IR applications

Over the course of many investigations, CsCl modified Ga-containing germanium sulfide glasses and ceramics have proven to have one of the best host matrixes for rare-earth element doping, creating an ideal material for optical sensing, as active medium for lasers, or in optical amplifiers and broad band sources. This particular study investigates the room- and cryogenic-temperature (via liquid nitrogen) fluorescence of 65GeS$_{\mathrm{2}}$-25Ga$_{\mathrm{2}}$S$_{\mathrm{3}}$-10CsCl glasses doped with Er. The emission spectra were recorded in 1000-1700 nm wavelength range, using excitation wavelengths from 300-950 nm (using Horiba Fluorolog-3 spectrometer). At room temperature, strong emission lines at \textasciitilde 1.55 m corresponding with \textasciitilde 530 nm excitation wavelength were observed in Er-doped samples. At liquid nitrogen temperature, the excitation wavelength for this emission line gradually shifted towards lower values (\textasciitilde 400-450 nm). These observed emission lines agree well with known energy level transitions of Er$^{\mathrm{3+}}$ ions incorporated in the glass matrix.