Dependence of fluorescence properties on substitution of BaF2 for BaO in barium gallo-germanate glass

Abstract 3.5 mol%, 6.5 mol%, 9.5 mol%, and 12.5 mol% BaF2 were gradually substituted for BaO in 0.3 mol% Tm2O3 doped 12.5 BaO–12.5 Ga2O3–75 GeO2 (BGG) glasses to study the effect of the substitution on the OH− elimination and emission properties. The FTIR spectral demonstrated that the substitution effectively eliminated OH− groups and 9.5 mol% BaF2 was enough for the OH− elimination. The J–O parameters of all the samples were calculated according to J–O theory. The calculation showed that the Ω2 parameter decreased monotonically with BaF2 content increasing, while Ω4 and Ω6 did not change much. The radiative lifetime increased while BaF2 content increased as well. The emission cross section of 3F4 → 3H6 transition was calculated by the F–L formula. However, it decreased with the gradual BaF2 addition. Research Highlights ► OH− groups were eliminated by the substitution of BaF2 for BaO in (BGG) glass. ► The optimal substitution level of BaF2 was 9.5 mol% for OH− elimination. ► The Ω2 parameter decreased monotonically by the elimination. ► The emission cross section of 3F4 → 3H6 transition was decreased by the substitution.