Yellow to violet upconversion of Nd³⁺ in neat Cs₂NaNdCl₆ elpasolite is demonstrated in this paper. Three intense bands have been observed at 367, 390 and 422 nm originating from ⁴D₃∕₂ multiplet upon the excitation of 595.5 nm, which is in resonance with the energy of ⁴G₅∕₂ level of Nd³⁺. The mechanism of the upconversion has been investigated through upconversion emission intensity dependence on the power of the pumping light and luminescence decay. It is found out that the upconversion is a two-photon process. The ground state absorption (GSA)/energy transfer upconversion (ETU) is responsible for the upconversion with comparison of the excitation spectrum and the one-photon absorption spectrum. Copyright © 2014 Elsevier B.V.
Two photon processes
CitationZhou, X., Zhao, X., Mak, C. S. K., Li, L., Lia, Q., & Tanner, P. A. (2014). Yellow to violet upconversion processes of Nd³⁺ in neat Cs₂NaNdCl₆ elpasolite. Optical Materials, 37, 24-27.