Upconversion luminescence and mechanisms in Yb3+-sensitized Tm3+-doped oxyhalide tellurite glasses

Effect of Yb2O3 content on upconversion luminescence and mechanisms in Yb3+-sensitized Tm3+-doped oxyhalide tellurite glasses were investigated under 980 nm excitation. Intense blue and relatively weak red upconversion emission centered at 476 and 649 nm corresponding to the transitions 1G4→3H6 and 1G4→3H4 of Tm3+, respectively, are simultaneously observed at room temperature. The results show that upconversion blue and red emission intensities of Tm3+ first increase, reach its maximum at Yb2O3%=3 mol%, and then decrease with increasing Yb2O3 content. The effect of Yb2O3 content on upconversion intensity is discussed, and possible effect mechanisms are evaluated. The investigated results were conducing to increase upconversion luminescence efficiency of Tm3+.