Energy transfer and 1.8μm emission in Tm~(3+)/Yb~(3+) codoped lanthanum tungsten tellurite glasses

摘要

Tm~(3+)/Yb~(3+)-codoped lanthanum tungsten tellurite (TWL) glasses are prepared by melt-quenching method and the thermal stability of the glasses is analyzed. To evaluate the spectroscopic properties of Tm~(3+) in TWL glass, the Judd–Ofelt intensity parameters (Ω_tt = 2, 4, 6), radiative transition rates, radiative lifetimes,and branching ratios of Tm~(3+) are calculated based on the absorption spectrum. The 1.8μm emission of the samples are investigated under the excitation of 980nm LD. Large product of emission cross-section and lifetime (σ_(em)τ_R) of Tm~(3+): ~3F_4→~3H_6 is obtained, and the maximum gain coefficient at around 1835nm is 3.6cm~(-1). The energy transfer processes of Yb~(3+)–Yb~(3+) and Yb~(3+)–Tm~(3+) are analyzed, the results show that the Yb~(3+) ions can transfer their energy to Tm~(3+) ions with a large energy transfer coefficient, and a maximum efficiency of 89%.