Structural, thermal and spectroscopic properties of Tm3+ doped TeO2-Bi2O3-ZnO glasses

We report the influence of Tm 3+ doping on the density, thermal, and spectral properties of TeO 2 –Bi 2 O 3 –ZnO tellurite glasses in order to develop a glass with promising lasing properties at 1.9 µm. All investigated compositions exhibit low phonon energies (∼747 cm −1 ) and low OH - content, leading to relatively low multiphonon relaxation rate. The fluorescence lifetime at 1.85 µm decreases rapidly with increasing Tm 3+ concentration due to concentration quenching via cross-relaxation. Analysis of lifetimes and cross-relaxation rates yields an optimum concentration of 0.55 mol% Tm 2 O 3 for maximum laser gain at ∼1.9 µm. A broad emission band with a 217 nm FWHM centered at 1.85 µm highlights the potential of these glasses for broadly tunable and short-pulse laser source at ∼1.9 µm. • Low-phonon Tm 3+ :TeO 2 –Bi 2 O 3 –ZnO glasses were prepared by melt quenching. • An exceptionally broad 217 nm emission bandwidth is obtained at 1.85 µm. • Cross-relaxation scales quadratically with Tm 3+ concentration and reduces lifetime. • Glass with 0.5 mol% of Tm 2 O 3 demonstrates the best gain efficiency at 1.9 μm. • Glasses show potential for CW, ultrafast, and tunable SWIR laser systems.