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.
