Mid-infrared luminescence properties of erbium and dysprosium doped lanthanum titanate glasses

Glasses of composition xRE2O3-(17-x) La2O3-83 TiO2 were prepared by levitation melting from x = 0.1 to 9 for RE=Er and at x =0.1 and 1 for RE=Dy. The glasses have high transition temperature, exhibit low OH, and 1 mm thick discs are transparent out to 6 mu m. Mid-infrared emission lineshapes and lifetimes are comparable to what is seen in tellurite glasses containing Er3+ and Dy3+. For x fixed at 1, the Er3+:4I11/2 -> 4I13/2 transition at 2716 nm has a fluorescence lifetime of 254 mu s and the Dy3+:6H13/2 -> 6H15/2 transition at 2957 nm has a fluorescence lifetime of 9.09 mu s. The results indicate that doped lanthanum titanate glasses offer the thermal stability of a 'hard' glass with the host properties typically associated with 'soft' glasses. Problems with the measurement of spectral features in the mid-infrared that could erroneously be assigned as resulting from rare-earth ion emissions are presented and discussed.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement