Effect of alkali halides on the emission properties in Tm‐doped chalcogenide glasses

Abstract

AbstractPhotoluminescence properties and local structure of Tm ions in Ge‐Ga‐Se glasses with the addition of alkali halides were investigated. The range of halide concentrations in the glass of composition (Ge26Ga9(Se+S)65)100‐x (Halide)x)99Tm1 (where x = 0–12 mol%, Halide = CsBr, CsI) were prepared by melt quenching methods. The luminescence lifetime of Tm3+ ions at 1780 nm band (3F4→3H6) increased with increasing alkali halide concentration. When the CsBr content is 10 mol%, the PL lifetime of the 1780 nm band increased about 4 times compared with that in the glass without CsBr. The 1460 nm band PL lifetime did not increase as much. The glass transition temperature decreased with increasing CsBr content. The effect of CsI addition is almost the same as the addition of CsBr. The addition of Br ions into the glass would result in the formation of Ga‐Br bonding. These phenomena in Ge‐Ga‐Se glasses are similar to those in Ge‐Ga‐S glasses with CsBr (Y.B. Shin et al., J. Mater. Res. 16, 1318 (2001) [1]). It is supposed that a complex such as a tetrahedral [GaSe3/2Br]– subunit is formed. The structure could be coordinated to Tm3+ ions. The local structure plays an important role in the emission properties of excited Tm3+ ions. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)