Luminescence thermal quenching ofCr3+in zirconium-barium-based fluoride glasses investigated by time-resolved laser spectroscopy

The optical properties of trivalent chromium ions in zirconium-barium-lanthanum fluoride glasses [${62\mathrm{Z}\mathrm{r}\mathrm{F}}_4$-${30\mathrm{B}\mathrm{a}\mathrm{F}}_2$-${8\mathrm{L}\mathrm{a}\mathrm{F}}_3$, ${57\mathrm{Z}\mathrm{r}\mathrm{F}}_4$-${34\mathrm{B}\mathrm{a}\mathrm{F}}_2$-${5\mathrm{L}\mathrm{a}\mathrm{F}}_3$-${4\mathrm{A}\mathrm{l}\mathrm{F}}_3$, and 58 ${\mathrm{ZrF}}_4$-${18\mathrm{B}\mathrm{a}\mathrm{F}}_2$-5.${5\mathrm{L}\mathrm{a}\mathrm{F}}_3$-${3\mathrm{A}\mathrm{l}\mathrm{F}}_3$-15NaF] have been investigated by using steady-state and time-resolved luminescence techniques. The thermal quenching of the broadband emission is discussed in terms of the quantum-mechanical single-configurational-coordinate model using the Struck-Fonger method, and good agreement with the experimental results is obtained. The quantum efficiencies for the three glasses are low in accordance with the strong thermal quenching of the luminescence, and the influence of the host material on their values can be well related with the parameters of the quantum-mechanical single-configurational-coordinate model. In order to correlate glass-matrix composition with emission spectral properties, detailed time-resolved measurements have been performed. The results obtained provide evidence for the assumption of two main statistical site distributions for ${\mathrm{Cr}}^{3+}$ in these glasses.