POPULATION-DYNAMICS IN YB-ER-PHOSPHATE GLASS UNDER NEODYMIUM LASER PUMPING

Characteristics of ytterbium to erbium energy transfer in Yb:Er:phosph ate glasses have been studied for a case when Nd phosphate glass laser is used as a pumping source. A theoretical model of the energy transf er was developed to reproduce the experimentally observed population d ynamics of the Er3+ upper and lower laser levels. The results show tha t saturation and frequency hole burning of the inhomogeneously broaden ed Yb3+ absorption line are of primary importance in determining the d ynamics and efficiency of the Yb3+-Er3+ energy transfer under Nd laser pumping. The influence of other loss channels that have been identifi ed in previous studies is found to be relatively small. The model also yields the lifetime of the frequency hole, as well as the effective r ates of energy transfer between groups of Yb3+ and Er3+ ions in phosph ate glasses.