Spectroscopic investigation of Tm3+: TeO2-WO3 glass

Abstract

We studied the spectroscopic characteristics of telluride glass with the host composition (0.85)TeO2–(0.15)WO3, containing 0.25 and 1.0 mol% thulium oxide (Tm2O3). By analyzing the absorption spectra with the Judd–Ofelt theory, the average radiative lifetimes of 305±7.5 μs and 1.95±0.02 ms were determined for the 3F4 and 3H4 levels, respectively. Measured fluorescence lifetime of the 3F4 level decreased from 218 to 51 μs for the 0.25 and 1.0 mol% Tm2O3 doped samples, respectively, indicating the effect of boosted non-radiative decay at higher doping concentrations. A similar trend was observed for the 3H4 level, where the fluorescence lifetime decreased from 1.86 ms to 350 μs at these concentrations. The quenching of the 1460 nm (3F4→3H4) emission in favor of the 1800 nm (3H4→3H6) emission due to cross relaxation was further evident in the fluorescence spectra of the samples. The calculated stimulated emission cross sections (3.73±0.1×10−21 cm2 at 1460 nm and 6.57±0.07×10−21 cm2 at 1808 nm) reveal the potential importance of the Tm3+:(0.85)TeO2–(0.15)WO3 glass for applications in fiber-optic amplifiers and fiber lasers.