Ultra-broadband 4.1 μm mid-infrared emission of Ho3+ realized by the introduction of Tm3+ and Ce3+

Abstract

Ho3+/Tm3+/Ce3+ tri-doped tellurite glasses with lower phonon energy (761 cm−1) were prepared by melt quenching in this paper. Performing XRD, Raman, DSC performance characterization, it was concluded that the synthetic tellurite glass sample had a multi-element structure, and the ΔT of the prepared tellurite glass was 138 °C, which can be used for fiber drawing with good thermal stability. Under the 808 nm LD excitation, an ultra-broadband emission from 3800 to 4200 nm mid-infrared band with full-width at half-maximum (FWHM) of the prepared glass about 309 nm was achieved, which can be applied to mid-infrared ultra-wide tunable all-fiber laser. With the introduction of CeO2, the up-conversion emission were suppressed and strong mid-infrared emission were obtained, at the same time, the fluorescence lifetime of the sample was significantly prolonged, which are mainly due to the cross relaxation between Ho3+ and Ce3+, the energy transfer mechanism was further analyzed through the energy level transition process. The maximum emission cross section and gain coefficient of the tellurite glass were 1.01 × 10−20 cm2 and 1.13 cm−1, which were improved compared with the previously reported tellurite glasses. The results demonstrate that the Ho3+/Tm3+/Ce3+ tri-doped tellurite glass is a promising mid-infrared optical material.