title: [Direct sensitization up-conversion mechanism from Yb3+ to Ho3+ and Tm3+ in fluoride].
abstract: The direct sensitization up-conversion processes from Yb3+ to Ho3+ and Tm3+ in fluoride were studied. The properties of the up-converted spectra of Yb3+ /Ho3+ and Ho3+ /Yb3+ /Tm3+ co-doped fluorides pumped by a 980 nm laser were compared. Their up-conversion mechanism has been analyzed and discussed. Two strong up-conversion luminescence bands have been observed, which were the transitions of 5 F4 5 S2 (Ho3+) -->18 (Ho3+) in the Yb3+ /Ho3+ co-doped fluoride system and 3 H4 (Tm3+) --> 3 H6 (Tm3+) in the Ho+ /Yb3+ /Tm3+ co-doped fluoride system. The addition of Tm3+ into Yb3+ /Ho3+ co-doped fluoride decreases the up-converted emission intensities of Ho3+ in the visible region.
authors.affiliation: Faculty of Material Science and Photoelectric Physics, Xiangtan University, Xiangtan 411105, China.
authors.forename: Xiang-Hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Zheng-Wei
authors.initials: ZW
authors.lastname: Liu
authors.forename: Si-Guo
authors.initials: SG
authors.lastname: Xiao
mesh_terms: D000465:Algorithms; D004735:Energy Transfer; D005459:Fluorides / Q000737:chemistry*; D006695:Holmium / Q000737:chemistry*; D007834:Lasers; D049449:Luminescence; D008163:Luminescent Measurements / Q000379:methods; D008956:Models, Chemical; D013053:Spectrophotometry; D013932:Thulium / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D013932:Thulium; D015018:Ytterbium; D005459:Fluorides; D006695:Holmium