This study examined spectroscopic, thermal, and other qualities, such as the lasing parameters, of Sm3+-doped glass with the composition 40P2O5–30ZnO–20LiCl–10BaF2. The ellipsometric data were used in a Sellmeier dispersion relation to estimate the refractive index values of the glasses investigated. The measured absorption spectra of the doped glass reveal the presence of various absorption bands assigned to transitions from the 6H5/2 ground state attributed to Sm3+-ion-excited states. We studied the decay of the 4G5/2 level of the Sm3+ ions in the doped glass by analyzing its absorption and emission fluorescence spectra. The Judd–Ofelt hypothesis allowed us to determine that the quantum efficiency of the 4G5/2–6H7/2 transition is high: 96% and 97% for glass doped with 4.05 × 1019 ions/cm−3 and 11 × 1019 ions/cm−3, respectively. Furthermore, this glass exhibits efficient red/orange enhanced spontaneous emission that matches the excitation band of the photosensitizer material used in medical applications.
