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2 July 1998 Excitation upconversion by sensitized photon avalanche
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Proceedings Volume 3405, ROMOPTO '97: Fifth Conference on Optics; (1998)
Event: ROMOPTO '97: Fifth Conference on Optics, 1997, Bucharest, Romania
The features of a new upconversion mechanism of excitation, the sensitized photon avalanche, are discussed on the basis of a rate equation modeling. In this process the excited state absorption (ESA) from a metastable level (reservoir) of the active ion is enhanced by a cross-relaxation between the emitting level of this ion and the sensitizer ion which is able to transfer subsequently the accepted excitation back into the reservoir level of the activator; the donor act of the cross-relaxation ends on this reservoir level too. When the efficiencies of these two energy transfer processes are larger than specific threshold values related to the intrinsic de-excitation rates of the emitting level of activator and of the excited level of sensitizer, a process of population of the reservoir level with a quantum efficiency larger than the unit for each act of de-excitation of the emitting level takes place. Further on, if the ESA rate exceeds a threshold value determined by the intrinsic de- excitation of the reservoir and by the efficiencies of the energy transfers an avalanche population of these levels could take place. This process could be used for infrared pumping of visible solid state lasers. The theory is illustrated for Yb3+- sensitized visible emission of Pr3+ under infrared pump (835 nm).
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Voicu Lupei, Eugen Osiac, T. Sandrock, Ernst Heumann, and Guenter Huber "Excitation upconversion by sensitized photon avalanche", Proc. SPIE 3405, ROMOPTO '97: Fifth Conference on Optics, (2 July 1998);

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