Absorption and emission spectral studies of Pr3+ and Tm3+ ions in PbO-PbF2 glasses

Absorption spectra of 30Pb0.69PbF 2 .1Ln 2 O 3 (Ln=Pr, Tm) have been analysed for spectral and Judd-Ofelt parameters. 3 P 0 ← 3 H 4 transition for Pr 3+ at 20704 cm -1 suggests 8-9 coordination. The Judd-Ofelt parameters for these rare earth ions are in the lower range of reported values and comparable to Ln 3+ in fluoride glasses. It is proposed that Ln 3+ ions go into sites with D 2h or lower symmetry predominantly surrounded by fluoride ions from PbO 2 F 4 units. The radiative parameters namely, transition probabilities (A, Ar), branching ratios (β r ) and lifetimes (τ r ) are obtained, β r values deduced form Judd-Ofelt parameters are in close agreement with experimental values obtained from emission spectra. The relavive fluorescence for these ions in this glass is much higher than in phosphate glasses and comparable to tellurite and germanate glasses