EXAFS investigation on the structural environment of Tm3+ in Ge–Ga–S–CsBr glasses

The local structures around Tm3+ in Ge0.25Ga0.10S0.65 and 0.90 (Ge0.25Ga0.10S0.65) − 0.10CsBr glasses were investigated using Extended X-ray absorption fine structure (EXAFS) spectroscopy. In Ge0.25Ga0.10S0.65 glass, Tm3+ ions are surrounded by approximately seven S ions. Addition of 10 mol% CsBr resulted in significant changes in the EXAFS spectrum of Tm3+ ions due to the changes in the local structure surrounding Tm3+ ions. The first-nearest coordination shell around Tm3+ ion is predominantly composed of about six Br ions in 0.90 (Ge0.25Ga0.10S0.65) − 0.10CsBr glass.