Efficient Sensitization ofHo3+Fluorescence

Abstract

Conservation of the energy of green-light excitation was observed in the infrared fluorescence of a calcium-erbium fluoride crystal sensitized with Tm${\mathrm{F}}_3$ and activated with Ho${\mathrm{F}}_3$. Only the 2-μm transition of ${\mathrm{Ho}}^{3+}$ 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.