Investigation of Tm³⁺/Yb³⁺ co-doped germanate–tellurite glasses for efficient 2 µm mid-infrared laser materials

Abstract

The Tm³⁺/Yb³⁺ co-doped germanate–tellurite glasses with good thermal properties were prepared. Based on the absorption spectra and the Judd–Ofelt theory, the J–O intensity parameters (Ω _t ), radiative transition probability (276.78 s^− 1), fluorescence lifetime (3.89 ms), absorption and emission cross sections (${\sigma _{\text{e}}}$ = 1.35 × 10^− 20 cm²) were calculated. The ~ 2 µm mid-infrared emission resulting from the ³F₄→³H₆ transition of Tm³⁺ sensitized by Yb³⁺ was observed pumped by 980 nm LD. Besides, the energy transfer mechanism between Yb³⁺ and Tm³⁺ was thoroughly discussed. The measured ~ 2 µm emission lifetime of Tm³⁺/Yb³⁺ co-doped glass can reach as high as 2.38 ms. The above results showed that Tm³⁺/Yb³⁺ co-doping glass could be expected to be a promising material to achieve high efficient ~ 2 µm lasing with a 980 nm LD pumping.