Mid-infrared spectroscopy of novel Er³⁺ doped indium modified chalcogenide glasses

In this work Er³⁺ doped chalcogenide glasses structurally modified by indium (In-ChG) was prepared. The mid-infrared spectroscopic properties and solubility of Er³⁺ in In-ChG was investigated and compared with those of gallium modified glasses (Ga-ChG). Thermal stability, mid-infrared (MIR) photoluminescence (PL), absorption spectra of both Ga-ChG and In-ChG were characterized and compared in parallel. Both the obtained MIR absorption and emission cross sections of In-ChG are higher than those of Ga-ChG. The theoretical branching ratio and decay lifetimes of ⁴I_11/2-⁴I_13/2 transition calculated from Judd-Ofelt theory were compared with those obtained from experiments. The tested and calculated lifetime is similar and it indicates high radiative quantum efficiency. Raman spectra reveal the fact that In-ChG possess lower phonon energy than that of Ga-ChG, which might possibly give rise to the improved MIR emission. Er³⁺ doped In-ChG chalcogenide glass is a potential material for MIR fiber laser application.