Energy transfer processes and heat generation in Yb~(3+)-doped phosphate glasses

摘要

In this work we present a study of energy transfer processes in Yb~(3+)-doped phosphate glasses with different OH~- contents and Yb~(3+) concentrations. Fluorescence and thermal lens (TL) techniques were used in order to analyze the Yb~(3+)-OH~- and Yb~(3+)-other impurity interactions. The role of OH~-groups is also presented and discussed. The results show that in the low concentration region up to ～3 X 10~(20) Yb ions/cm~3, the interaction between Yb~(3+) and OH radicals is the dominant process reducing the lifetime, increasing the TL dioptric power, and then endangering the performance of the system. For the high Yb~(3+) concentration limit, the Yb~(3+)-other impurity interaction, which is favored by energy migration, is comparable to the Yb~(3+)-OH~- energy transfer, even for high OH~- concentration. The nonradiative decay rate due to hydroxyl groups follows Foerster-Dexter theory [Ann. Phys. 2, 55 (1948); J. Chem. Phys. 21, 836 (1953)] except at low Yb~(3+) concentration, being more active at low OH~- levels, where quenching rate is probably due to several impurities.