Broadband 2.9 μm and 4.1 μm mid-infrared emission and energy transfer mechanisms in Ho3+/Yb3+ co-doped tellurite glasses

Ho 3+ /Yb 3+ co-doped tellurite glasses were synthesized through the use of the conventional melt-quenching method in this paper. Under the excitation of 980 nm LD , an intense and broad 4.1 μm mid-infrared fluorescence of the wavelength range from 3600 to 4400 nm with the full width at half maxima (FWHM) of the fabricated glasses about 343 nm were obtained, which have potential applications in the field of wide band mid-infrared lasers. Meanwhile, strong 2.9 μm mid-infrared emission (2730–3030 nm) was observed with the FWHM of 109 nm and the calculated maximum gain coefficient reach to 2.16 cm −1 around 2843 nm. The intense visible up-conversion emission bands center at 551, 662 and 753 nm, near-infrared fluorescence emissions around 1.2 and 2.0 μm were observed in the synthetic tellurite glasses. Under the different concentration of Yb 2 O 3 , a series of luminescence properties were detailed researched. In addition, the energy transfer mechanism was discussed according to the emission spectra and the fluorescence lifetime value of the change trend. These findings demonstrate that the synthesized Ho 3+ /Yb 3+ co-doped tellurite glasses exhibit excellent fluorescence properties for mid-infrared laser materials.