EFFICIENT SENSITIZATION OF HO3+ FLUORESCENCE

Conservation of the energy of green-light excitation was observed in the infrared fluorescence of a calcium-erbium fluoride crystal sensitized with TmF3 and activated with HoF3. Only the 2-m transition of Ho3+ fluoresced at 77°K. Quantum yields up to 540% were observed in the fluorescence excitation spectrum. The linewidths, efficiency of fluorescence sensitization, and temperature dependence indicated ion-lattice interactions secondary to a resonant and nonresonant ion-ion interaction which was assigned to exchange. © 1969 The American Physical Society.