Composition dependence of the Judd-Ofelt intensity parameters in TeO 2-PbF 2 : Tm 3+ glasses

Abstract

Tm 3+ -doped glasses with the composition of (1-x)TeO 2-xPbF 2, where x=10, 15, 20, 25 mol.% were synthesized and, their thermal and absorption measurements were investigated. All the glasses were transparent. The absorption bands corresponding to the absorption of the 1G 4, 3F 2, 3 3, 3F 4, 3H 4, and 3H 4 levels from the 3H 6 ground level of the Tm 3+ ion were observed in the optical UV/VIS/NIR absorption measurements. We calculated the integrated absorption cross sections of each band except that of 3H 5 level was found to vary with composition of the PbF 2. The absorption measurements were first made to determine the spontaneous emission probabilities of the 4f-4f transitions of the Tm 3+ ions. The calculations were made by using the Judd - Ofelt theory. The Ω 2 parameter shows the strongest dependence on the host composition and it increases with the increasing PbF 2 amount. The values 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 symmetry of the local environment of the Tm 3+ ions in this glass.