Mid-infrared fluorescence, energy transfer process and rate equation analysis in Er3+ doped germanate glass

Abstract

Er3+ doped Y2O3 and Nb2O 5 modified germanate glasses with different Er3+ concentrations were prepared. J-O intensity parameters were computed to estimate the structural changes due to the additions of Y2O3 and Nb2O5. The main mid-infrared spectroscopic features were investigated. To shed light on the observed mid-infrared radiative behavior, 975nm and 1.53μm emission spectra along with their decay lifetimes were also discussed. Moreover, the energy transfer processes of 4I 11/2 and 4I13/2 level were quantitatively analyzed. In view of the experimental lifetimes, the simplified rate equation was utilized to calculate the energy transfer upconversion processes of upper and lower laser level of 2.7μm emission. The theoretical calculations are in good agreement with the observed 2.7μm fluorescence phenomena. Finally, the stimulated emission and gain cross sections were calculated and the results indicate that Er3+ doped germanate glasses have great potential for mid-infrared application.