Thermal stability and broadband NIR luminescence of Pr³⁺ doped gallo-germanate glasses with BaF₂ have been studied. The thermal factors are larger for glass samples with low BaF₂ content exhibiting good thermal stability against devitrification. Luminescence due to ¹D₂ → ¹G₄ transition of Pr³⁺ was measured under 450 nm excitation. The ¹D₂ measured lifetimes depend critically on activator concentration, but remain nearly unchanged with BaF₂ content. The emission linewidth, the emission cross-section, the figure of merit (FOM) and the σ_em x FWHM product are relatively large, suggesting that Pr³⁺-doped gallo-germanate glasses with presence of BaF₂ are promising as gain media for broadband near-infrared amplifiers.

The ErF₃-doped oxyfluoride phospho-tellurite glasses in the (40-x) TeO₂-10P₂O₅-45 (BaF₂-ZnF₂) -5Na₂O-xErF₃ system (where x = 0.25, 0.50, 0.75, 1.00, and 1.25 mol%) have been prepared by the conventional melt-quenching method. The effect of erbium trifluoride addition on thermal, structure, and spectroscopic properties of oxyfluoride phospho-tellurite precursor glass was studied by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and Raman spectroscopy as well as emission measurements, respectively. The DSC curves were used to investigate characteristic temperatures and thermal stability of the precursor glass doped with varying content of ErF₃. FTIR and Raman spectra were introduced to characterize the evolution of structure and phonon energy of the glasses. It was found that the addition of ErF₃ up to 1.25 mol% into the chemical composition of phospho-tellurite precursor glass enhanced 2.7 µm emission and upconversion. By controlled heat-treatment process of the host glass doped with the highest content of erbium trifluoride (1.25 mol%), transparent erbium-doped phospho-tellurite glass-ceramic (GC) was obtained. X-ray diffraction analysis confirmed the presence of BaF₂ nanocrystals with the average 16 nm diameter in a glass matrix. Moreover, MIR, NIR, and UC emissions of the glass-ceramic were discussed in detail and compared to the spectroscopic properties of the glass doped with 1.25 mol% of ErF₃ (the base glass).