Mechanisms of up-conversion excitation of blue emission in YAG:Tm, Yb

A. KNÜPFER; V. OSTROUMOV; E. HEUMANN; G. HUBER; V. LUPEI

doi:doi:10.1051/jp4:19944120

3rd International Conference Laser M2P

J. Phys. IV France 04 (1994) C4-501-C4-504
DOI: 10.1051/jp4:19944120

Mechanisms of up-conversion excitation of blue emission in YAG:Tm, Yb

A. KNÜPFER¹, V. OSTROUMOV¹, E. HEUMANN¹, G. HUBER¹ and V. LUPEI²

¹ Universität Hamburg, Institut für Laser-Physik, Jungiusstrasse 11, 20355 Hamburg, Germany
² Institute of Atomic Physics, Bucharest 76900, Romania

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 ²F_5/2 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.