Theory on cooperative quantum transitions of three identical lanthanide ions

摘要

Recently, we observed ultraviolet luminescence in CaF2:Yb3+ under the excitation of a 980 nm laser. In this paper, cooperative transition theory of three identical lanthanide ions is built through perturbed wave functions of a three-body system with electric multipole interactions. The theoretical results show that d-dd-dq and crystal field effected d-dd-dfd are the main mechanisms in the triple transition processes. The transition rate ratio of Yb3+ -dimers and Yb3+-trimers in an Yb3+-hexamer is calculated to be similar to 1.86 x 10(4). This is in reasonable agreement with the experimentally obtained cooperative luminescence intensity ratio of similar to 2.0 x 10(4) in CaF2:Yb3+ under the excitation of a 980 nm laser. (C) 2015 Optical Society of America