Upconversion Luminescence in Nd3+: LaCl3

Blue and near violet upconversion luminescence originating from4D3/2and2G9/2levels in Nd3+:LaCl3can be induced upon excitation into2G7/2+4G5/2in the yellow region. Upconversion occurs via an energy transfer mechanism with or without excited-state absorption. Analysis of the upconversion tran-sient of4D3/2→4I11/2radiative transition at 12K leads to a rate constantwt1=1468 s-1for the energy transfer step. The lifetimes of the main fluorescence levels of Nd3+: LaCl3and NdCl3in the visible range were measured and the values are compared and discussed.