Energy transfer from Tm^3+:^3H_5 to Dy^3+:^6F_11/2 ^6H_9/2 in selenide glasses

The effects of Tm3+ ions on the intensity and lifetime of 1.3 µm fluorescence from Dy3+ ions in Ge25Ga5Sb5Se65 glass were investigated, and the energy-transfer mechanisms were discussed. Tm3+ codoping in Dy3+-doped selenide glasses significantly enhanced the 1.3 µm fluorescence intensity and remarkably increased corresponding lifetime through an efficient energy transfer from Tm3+:3H5 to Dy3+:6F11/26H9/2. The donor (Tm3+) excitation was transferred to the acceptor (Dy3+) by direct electric dipole-dipole interaction or migrated among donor ions by diffusion-limited regime until it came into the vicinity of an acceptor ion, where direct interaction and transfer occurred.