Improved thermal stability and intense blue upconversion in Yb~(3+)/Nd~(3+)/Tm~(3+) tri-doped tellurite glasses

摘要

New Yb~(3+)/Nd~*(3+)/Tm~(3+) tri-doped tellurite glasses (TeO_2-Bi_2O_3-ZnO-Na_2O) with improved thermal stability and intense blue upconversion emission were prepared by melt-quenching technique. The thermal stability and blue upconversion of glass samples were investigated by means of differential scanning calorimeter (DSC) and fluorescent spectrophotometer measurements. DSC results show that the prepared tellurite glasses have favorable thermal stability for fiber drawing and the difference (ΔT) between the estimated crystallization onset temperature (T_x) and the transition temperature (T_g) reaches about 186 ℃, which is larger than that of some other tellurite glass hosts. Under the excitation of 980 nm laser diode (LD), the tri-doped glass samples exhibit an intense blue (～474, 485 nm) upconversion emission, which is attributed to the simultaneous contributions from Tm~(3+):~1G_4→~3H_6 and Nd~(3+):~2G_(9/2)→~4I_(9/2) transitions, and the possible upconversion luminescent mechanism based on the energy transfers from Yb~(3+) is presented. The above results indicate that the new synthesized Yb~(3+)/Nd~(3+)/Tm~(3+) tri-doped tellurite glass is a promising candidate applied for the blue solid-state lasers.