Energy migration and transfer of Tm~(3+) -Gd~(3+) -Dy~(3+) system in NaGdF_4 under VUV and UV excitations

摘要

Based on the basis of the quantum cutting principle, the possibility to obtain two blue photons under excitation of one VUV photon in NaGdF_4:Tm~(3+), Dy~(3+) has been studied using spectroscopic technique. The Gd~(3+) → Dy~(3+) transfer preceded by energy migration among the Gd~(3+) ions is mainly governed by the exchange interaction. The quantum efficiencies for the Gd~(3+) → Dy~(3+) energy transfer have an optimal value for acceptor concentration at about N_A = 0.6 at% and concentration quenching can be observed obviously.