J. Phys. IV France 04 (1994) C4-537-C4-540
Site-selective upconversion in Ho3+ doped fluorite crystals MF2 (M=Ca,Sr,Cd)X. ZHANG1, J.P. JOUART2, M. BOUFFARD2 and G. MARY2
1 on leave from Changchun Institute of Physics, Academia Sinica
2 Laboratoire d'Energétique et d'Optique, GRSM, Université de Reims, BP. 347, 51062 Reims cedex, France
With tunable dye laser (620-660 nm) excitation, the site-selective upconversion properties of 0.1 mole% Ho3+ doped CaF2, SrF2 and CdF2 monocrystals were studied at 77K. Three distinct luminescence centres (C4v, C3v and cluster) were identified for both CaF2 and SrF2 crystals, whereas only one cluster centre was detected for CdF2. The upconversion mechanism for the isolated Ho3+ single site (C4v or C3v) is different from that for the cluster centre, with a two-step excitation process for the former and an energy transfer process for the latter.
© EDP Sciences 1994