Spectroscopic properties ofP13andP03excited states ofBi3+ions in germanate glass

Laser-induced-fluorescence-band-narrowing and time-resolved-spectroscopy techniques are extended to measure the inequivalent sites in the spectroscopic properties of ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}$ excited states of the ${\mathrm{Bi}}^{3+}$ ion in germanate glass. Under excitation of the ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ components, at 4 K, the analysis of the ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}\to {}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ unsplit fluorescence band is particularly useful to probe the large site-to-site variations in the glass. The spectral dependence of the lifetime, the temporal evolution of the bandwidth under laser excitation, the red shift of both ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}\rightleftarrows {}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}\to {}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ transitions and the strong intensity of the forbidden ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}\to {}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ transition are discussed. These experiments measure, indeed, the degree of inhomogeneity of ${\mathrm{Bi}}^{3+}$-doped germanate with a broadband ion for the first time.