Broadband near infrared emission of Er³⁺/Yb³⁺ co-doped fluorotellurite glass

TeO₂-AlF₃-NaF-BaF₂-LaF₃ glasses containing both Er³⁺ and Yb³⁺ were prepared by conventional quenching melt method. Differential scanning calorimeter (DSC) curve displays good thermal stability with glass transition temperature larger than 426.38 °C. Urbach energy was found to be 0.05 eV indicating few defects in prepared glass and its high homogeneity. Based on optical absorption spectra, important spectroscopic parameters are investigated to predict the potential luminescent properties in near-infrared band. Intense Er³⁺ emission around 1.53 µm corresponding to the transition of ⁴I_13/2 → ⁴I_15/2 upon 980 nm excitation. Effective bandwidth (Δλ_eff) over 100 nm after introducing 4 mol% amount of ErF₃ implies that Er³⁺/Yb³⁺ co-doped those glasses possesses excellent broadband luminescent property around 1.53 µm.