Effects of chloride introduction on up-conversion luminescence in Tm3+ -doped tellurite glasses

Blue up-conversion luminescence properties in Tm3+ -doped lead chloride tellurite glasses have been studied under 980 nm excitation. The intense blue and relatively weak red emissions 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 effect of PbCl2 on up-conversion intensity is observed and discussed, and possible up-conversion mechanisms are evaluated. The intense blue up-conversion luminescence of Tm3+ -doped lead chloride tellurite glasses may be a potentially useful material for developing up-conversion optical devices.