Luminescence of Sm 2+ -doped fluoride glasses

Abstract

We have investigated the optical properties of Sm 2+ -doped fluoride glasses having three different compositions. The absorption and emission spectra reveal that the immediate fluorine environment surrounding the Sm 2+ ion is nearly identical for the three glass compositions, and is probably characterized by a high coordination number. The emission yield, on the other hand, is sensitively dependent on the composition of the glasses. It is theorized that the interaction of the host conduction band with the 4f 55d and 5D 0 states is largely responsible for opening up a nonradiative decay pathway from the 5D 0 emitting level, to the 7F ground state levels. As a consequence, the glasses based on heavy metal ions give smaller emission yields than those primarily based on smaller cations.