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

Abstract

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 t t = 2, 4, 6), radiative transition rates, radiative lifetimes, and branching ratios of Tm 3+ are calculated based on the absorption spectrum. The 1.8 μm emission of the samples are investigated under the excitation of 980 nm 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 1835 nm is 3.6 cm −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%.