Spectroscopic study of Er-doped Ga2Ge5S13 glass for mid-IR laser applications

We present mid-IR spectroscopic characterization of the low-phonon chalcogenide glass, Ga2Ge5S13 (GGS) doped with Er3+ ions. Under the excitation at similar to 800 nm, Er3+:GGS exhibited broad mid-IR emission bands centered at similar to 2.7, similar to 3.5, and similar to 4.5 mu m at room temperature. The emission lifetime of the 4I9/2 level of Er3+ ions in GGS glass was found to be millisecondlong at room temperature. The measured fluorescence lifetimes were nearly independent of temperature, indicating negligibly small nonradiative decay rate for the 4I9/2 state, as can be expected for a low-maximum-phonon energy host. The transition line-strengths, radiative lifetimes, fluorescence branching ratios were calculated by using the Judd-Ofelt method. The peak stimulated emission cross-section of the 4I9/2 -> 4I11/2 transition of Er3+ ion was determined to be similar to 0.10x10-20 cm2 at room temperature. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement