RE3+ emission in garnets:: multisites, energy transfer and quantum efficiency

The connection between the high-resolution spectral disordering of the rare earth-doped garnets and the manifestation or the energy transfer in the global or selective emission decay is discussed. It is shown that the identification of the pair satellites and the investigation of their decay properties are important for determination or verification of the mechanisms of interaction that determine the energy transfer in simply activated or in sensitized crystals. The competition of various energy transfer processes in de-excitation of the metastable levels such as down-conversion and up-conversion in Nd: YAG under high intensity pump is discussed. It is shown that the energy transfer parameters determined from the emission decay could give a consistent description of data on quantum efficiency or heating effects. (C) 2002 Elsevier Science B.V. All rights reserved.