title: Investigation of radiative and nonradiative relaxation by two-photon resonant excitation in Tm3+ doped LaF3 particles.
abstract: Nano-scaled and micro-scaled Tm(3+)-doped LaF3 were prepared by a hydrothermal technique. Two-photon resonant excitation from the ground state 3H6 to the excited state 1D2 was fulfilled by two pulsed dye lasers tuned at 656 nm and 643 nm, respectively, which were resonant with the ground state absorption of 3H6 --> 3F2 and the excited state absorption of 3H4 --> 1D2. The time evolution of the corresponding state was investigated with blue upconverted emission by tuning the delay of two excitation lights. The results showed that the nonradiative relaxation of the 3F2 state was mainly affected by the confinement effect, while the radiative relaxation of 3H4 state was significantly influenced by the Tm3+ concentration.
authors.affiliation: College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, PR China.
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Fu
authors.forename: Hairong
authors.initials: H
authors.lastname: Zheng
authors.forename: Yu
authors.initials: Y
authors.lastname: Lei
authors.forename: Enjie
authors.initials: E
authors.lastname: He
authors.forename: Xisheng
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhenglong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Liangmin
authors.initials: L
authors.lastname: Xu