Spectroscopic investigation of Er³⁺ in fluorotellurite glasses for 2.7 μm luminescence

Er³⁺ doped fluorotellurite glass (TeO₂–BaF₂–NaF) with different Er³⁺ concentrations were prepared, glass thermal stability and structure were investigated by differential scanning calorimetry (DSC) test and Raman spectrum, respectively. 2.7 μm light emission was observed under 980 nm excitation in these fluorotellurite glasses. The 2.7 μm emission properties were investigated through the measured absorption and emission spectra. The spontaneous transition probability (A), branching ratio (β), emission and absorption cross sections were calculated and the values were relatively larger than some reported values, which indicated that this kind of fluorotellurite glass has potential application as host material for 2.7 μm lasers. - Highlights: • High T_g (375 °C) provides good thermal stability to resist thermal damage. • The introduction of F⁻ decreases the connectivity of the tellurite former network. • Er³⁺ doped TBN glasses have been investigated using Judd–Ofelt (JO) theory. • TBN glasses possess high stimulated emission cross section σ_e for 2.7 μm emission