Broadband ∼2μm emission in Tm3+/Ho3+ co-doped TeO2-WO3-La2O3 glass

In this work, we report the infrared emission properties of Tm3+/Ho3+ co-doped TeO2-WO3-La2O3 (TWL) glass under 808 nm laser excitation. A broad and flat emission from 1600 to 2200 nm corresponding to the Tm3+ (3F4→3H6) and Ho3+ (5I7→5I8) emissions is observed. The full width at half maximum (FWHM) of this broadband increases up to a value of ∼370 nm with an optimal [Tm3+]/[Ho3+] concentration ratio. The energy transfer processes of Tm3+↔Ho3+ are analyzed and the results show that energy transfer between Tm3+ and Ho3+ plays an important role in the luminescence mechanism. The OH− influence on the broadband emission is also discussed. These results indicate that Tm3+-Ho3+ co-doped TWL glass could be a promising material for widely tunable laser or broadband amplifier applications.