Energy transfer processes in rare-earth-ion-doped materials

Energy transfer characteristics for Yb3+ to Tm3+ ions have been investigate d in order to carry out characterization of the host materials and to obtai n proper improvement procedures for the conventional rate equation model. E xperimental investigations were carried out particularly for YAG as the hos t material and the results were compared with the results obtained for seve ral fluoride lattices. It has been shown that the energy transfer coefficie nt from Yb3+ to Tm3+ ions is larger and more strongly dependent upon Yb3+ i on concentration in YAG than in the fluoride lattices. These experimental r esults have been compared with the results of Monte Carlo simulation carrie d out on a microscopic model. The dependence of the energy transfer coeffic ient on the donor concentration as well as that upon the host materials are explained systematically with the microscopic model. (C) 2000 Elsevier Sci ence B.V. All rights reserved.