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

Abstract

We report the influence of Tm3+ doping on the density, thermal, and spectral properties of TeO2–Bi2O3–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 Tm3+ concentration due to concentration quenching via cross-relaxation. Analysis of lifetimes and cross-relaxation rates yields an optimum concentration of 0.55 mol% Tm2O3 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.