Influence of BaF_2 and activator concentration on broadband near-infrared luminescence of Pr^3+ ions in gallo-germanate glasses

Thermal stability and broadband NIR luminescence of Pr(3+) 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 (1)D2 → (1)G4 transition of Pr(3+) was measured under 450 nm excitation. The (1)D2 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 σem x FWHM product are relatively large, suggesting that Pr(3+)-doped gallo-germanate glasses with presence of BaF2 are promising as gain media for broadband near-infrared amplifiers.