Spectroscopic properties of and energy transfer in PbO-Bi2O3-Ga2O3 glass doped with Er2O3

Er2O3-doped PbO-Bi2O3-Ga2O3 glasses were prepared through the conventional melt-quenching method, and the energy transfer mechanisms in Er3+ were inve stigated. The fluorescent emission at 2.73 mu m, which is normally quenched in silicate glasses, became evident because of the low phonon energy of Pb O-Bi2O3-Ga2O3 glasses. The measured lifetime of the upper level of I-4(11/2 ) was 0.9 ms, and it decreased to similar to 0.6 ms with increased Er3+ con centration. When the concentration of Er2O3 was 0.05 wt%, the coefficient o f the cross-relaxation rate for the I-4(11/2) level was similar to 18 times larger than that of the I-4(13/2) level. On the other hand, the interactio n parameter of energy migration was considerably larger for the I-4(13/2) l evel (similar to 52 x 10(-40) cm(6).s(-1)) compared with the I-4(11/2) leve l (similar to 3.1 x 10(-10) cm(6).s(-1)). Therefore, the major energy trans fer mechanism associated with the I-4(13/2), level was migration induced, w hereas that for the I-4(11/2) level was direct cross relaxation of I-4(11/2 ):I-4(11/2) --> F-4(7/2):I-4(15/2).