MULTIPLE SENSITIZATION EFFECTS IN CAF2 YB+ND

Transfer of energy between three different ions has been observed in CaF2 doped with Yb and Nd. In CaF2, Nd occurs in only the trivalent state, while Yb forms both divalent and trivalent luminescent centers. Evidence for both Yb2+→Nd3+ and Nd 3+→Yb3+ energy transfer is presented. Measurement and analysis of Yb2+ fluorescence decay times in crystals containing 0.1 mole % Yb and 1.0 mole % Nd, gave a figure of 0.62 for nonradiative transfer efficiency at 77°K. Sensitization of Yb3+ by Nd3+ produces strong ir emission, principally at 0.9752μ. An approximate estimate of sensitized increase of Yb3+ emission achieved approaches two orders of magnitude. © 1968 The American Institute of Physics.