Two-photon excitation of the 4f5d band of Pr3+ and interconfigurational energy transfer in LaF3:(Pr3+,Gd3+).

Abstract

Two-photon stepwise excitation of the 4f5d band of ${\mathrm{Pr}}^{3+}$ using as a real intermediate level $^{1}\mathrm{D}_{2}$ state is demonstrated in a Pr- and Gd-doped ${\mathrm{LaF}}_{3}$ crystal. Strong fluorescence arising from the $^{6}\mathrm{P}_{7/2}$ level of ${\mathrm{Gd}}^{3+}$ provides the first evidence of interconfigurational energy transfer between ${\mathrm{Pr}}^{3+}$ and ${\mathrm{Gd}}^{3+}$ ions in a solid. The mechanisms involved in this energy transfer are discussed.