Temperature dependence of the YAG:Cr3+fluorescence lifetime over the range 77 to 900 K

The YAG:${\mathrm{Cr}}^{3+}$ fluorescence lifetimes over the temperature range from 293 to 900 K are presented and, together with published data from 77 to ∼425 K, are examined using the single-configurational-coordinate model. The results show that the phonon-induced transitions between the ${}_{}{}^2{}_{}{}^{}$E and ${}_{}{}^4{}_{}{}^{}$ ${\mathit{A}}_2$ states have a significant effect on the lifetime of the YAG:${\mathrm{Cr}}^{3+}$ fluorescence at low temperatures. A concept of a single equivalent phonon is proposed to account for the mixing effects of phonons with various energy, and is used to modify the single-configurational-coordinate model discussed.