Abstract : A strong green emission of U/sup 3+/ ions in LaCl/sub 3/ under red excitation has been observed for the first time. The main anti-Stokes fluorescence arises from the U/sup 3+2/K/sub 15/2/ state (around 550 nm). Theoretical analysis and decaytime measurement of the induced fluorescence show that there are two mechanisms for the up-conversion. The first one consists in excited state absorption and the other one is due to energy transfer between two U/sup 3+/ ions in the /sup 4/F/sub 9/2/ state. In addition a detailed study of infrared emission spectra of LaCl/sub 3/:U/sup 3+/ has been carried out and lifetimes of main fluorescent levels were measured at low temperature. From this study three new experimental levels have been assigned.
M. Yin, M.F. Joubert, J.C. Krupa. Green up-conversion and infrared emission spectra of U$^{3+}$ in LaCl$_3$/. Journal of Alloys and Compounds, Elsevier, 1997, 260, pp.64-69. ⟨in2p3-00022975⟩