Thermal properties and optical transition probabilities of Tm 3+ doped TeO 2–WO 3 glass

Abstract

Glasses with the composition of (1− x)TeO 2+( x)WO 3, where x=0.15, 0.25 and 0.3 were prepared and, their thermal and absorption measurements were carried out. Differential thermal analysis (DTA) curves taken in the 23–600°C temperature range with a heating rate of 10°C/min reveal a change in the value of the glass transition temperature, T g, while crystallization was not observed for the glasses containing a WO 3 content of more than 15 mol%. All the glasses were found to be moisture-resistant. The absorption bands corresponding to the absorption of the 1G 4, 3F 2, 3F 3 and 3F 4, 3H 5 and 3H 4 levels from the 3H 6 ground level of the Tm 3+ ion were observed in the optical absorption spectra. Integrated absorption cross-sections of each band except that of 3H 5 level was found to vary with the glass composition. Judd–Ofelt analysis was carried out for the samples doped with 1.0 mol% Tm 2O 3. The Ω 2 parameter shows the strongest dependence on the host composition and it increases with the increasing WO 3 amount. The value of Ω 4 increases rather slowly while the value of Ω 6 is practically independent of the composition. The strong dependence of the parameter Ω 2 indicates that this parameter is related to the structural change and the symmetry of the local environment of the Tm 3+ ions in this glass.