Journal de Physique IV (Proceedings)
Mechanisms of up-conversion excitation of blue emission in YAG:Tm, Yb
A. KNÜPFER, V. Ostroumov, ERNST HEUMANN, Günter Huber, Voicu Lupei
Abstract
Trivalent ytterbium ions were used as sensitizers for the 1D2 and 1G4 blue emitting thulium levels. The evolution of the population of the 1D2, 1G4, 3H4, 3F4 levels of Tm3+ and the 2F5/2 level of Yb3+ were investigated after short resonant excitation into these levels in YAG:Tm, Yb crystals. We observed upconversion fluorescence with a fast cooperative process followed by a slower step-by-step-process.