Energy transfer in GGG:Yb3+,Ho3+ crystals

The energy transfer between Yb3+ and Ho3+ ions and the energy migration on Yb3+ ions as a function of temperature were studied in gadolinium gallium garnet crystals doped with Yb3+ (5%) and Ho3+ (3%). It was found that the commonly accepted energy transfer theories do not provide a good description of the system studied. The application of several theories gives contradictory results.