The violet and green fluorescence spectra and the kinetics of fluorescence decay in Er~ 3+ ∶YAG crystal under 408.6 nm excitation were investigated by the time-resolved laser-induced fluorescence technique. The influence of multiphonon and energy transfer on the fluorescence decay of the ~4S_ 3/2 multiplet were theoretically analyzed. A good agreement of the measured and the simulated decay curves was achieved. The continuous profile variety of the decay curves in the region from 548 to 561.2 nm is found and it originates from the fluorescence overlap of ~2G_ 9/2 and ~4S_ 3/2 and the intensity ratio dominates the profile.
The two-photon absorption(TPA)and TPA-induced frequency upconversion emission properties of the dyes 4-[P-(dicyanoethylamino)crystal]-N-methypyrdinium iodide and the complex of 4-[P-(dicyanoethylamino)crystal]-N-methypyrdinium iodide and Ce(NO3)3 were experimentally studied.It was found that the TPA cross section for the dye sensitized by Ce3+ is two factors larger than that of the dye without being sensitized.A three-level system model of the dye molecules was used to analyze the enhancement of TPA by the sensitizer Ce3+,which indicated that the sensitizer results in the increase of the transition dipole moment from the one-photon allowed excited state(1Bu)to the two-photon allowed excited state(2Ag).
LI Jian-fuSUN Cheng-linZHOU Hai-lingXU Li-huaYANG Qing-xinJIANG Zhan-kui
