The unusual temperature dependence of the Eu fluorescence lifetime in CaF2 crystals

Fluorescence lifetimes of Eu doped in CaF2 are measured at various temperatures between 4K and 450K. The lifetime increases with between 100K and 300K, in contrast to the usual lifetime-temperature dependence. At higher or lower temperatures the lifetime decreases with increasing temperature. The phenomenon is explained by simulation of the energy levels and lifetimes of low-lying 4f5d states involved in the fluorescence. Rare Earth ’04 in Nara, Japan, November 7-12, 2004, Paper FP-21 Corresponding Author: Dr. Michael F. Reid, [email protected] Department of Physics and Astronomy, University of Canterbury Christchurch, New Zealand. Phone: + 64 3 364 2548 Fax: + 64 3 364 2469 Preprint submitted to Elsevier Preprint 2 February 2008