We performed a comparative spectroscopic analysis on three novel Tm3+:tellurite-based glasses with the following compositions Tm2O3:TeO2-ZnO (TeZnTm), Tm2O3:TeO2-Nb2O5 (TeNbTm), and Tm3+:TeO2-K2
[...] Read more.
We performed a comparative spectroscopic analysis on three novel Tm3+
:tellurite-based glasses with the following compositions Tm2
-ZnO (TeZnTm), Tm2
(TeNbTm), and Tm3+
(TeNbKTm), primarily for 2-μm laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of Tm3+
ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies. By performing Judd–Ofelt analysis, we determined the average radiative lifetimes of the 3
level to be 2.55 ± 0.07 ms, 2.76 ± 0.03 ms and 2.57 ± 0.20 ms for the TeZnTm, TeNbTm and TeNbKTm samples, respectively. We clearly observed the effect of the cross-relaxation, which becomes significant at higher Tm2
concentrations, leading to the quenching of 1460-nm emission and enhancement of 1860-nm emission. Furthermore, with increasing Tm2
concentrations, we observed a decrease in the fluorescence lifetimes as a result of the onset of non-radiative decay. For the 3
level, the highest obtained quantum efficiency was 32% for the samples with the lowest Tm2
ion concentration. For the 1860-nm emission band, the average emission cross section was determined to measure around 6.33 ± 0.34 × 10−21
, revealing the potential of thulium-doped tellurite gain media for 2-μm laser applications in bulk and fiber configurations.