Enhanced 2.7 µm mid-infrared emission in Er3+/Ho3+ co-doped tellurite glass

Abstract Improving the mid-infrared band luminescent intensity in oxide glass system is a serious challenge. In this work, Ho3+ ions was introduced into Er3+ doped tellurite glass, and the improved effect on 2.7 µm band fluorescence of Er3+ was investigated. It was found that when 0.5 mol% of Ho2O3 was incorporated into the tellurite glass with 0.5 mol% of Er2O3, the 2.7 µm band fluorescence intensity originating from Er3+:4I11/2 → 4I13/2 transition increased by about 39% under the excitation of 808 nm laser diode (LD). This significant enhancement was attributed to the energy transfers between Er3+ and Ho3+ ions which improved the population inversion ratio of this emission transition. Analyses of the intensity variations of visible and infrared band emissions as well as the fluorescence decay behavior of Er3+ ions with Ho3+ doped concentration demonstrated the existence of energy transfers, and the energy transfer mechanism was investigated by calculating the relevant micro-parameters to better clarify the origin of fluorescence enhancement. Additionally, Judd-Ofelt theory was applied to the absorption spectrum and the potential spectroscopic properties of Er3+ were evaluated, while DSC curves revealed the good thermal stability of the studied tellurite glass. All these indicated that Er3+/Ho3+ co-doped tellurite glass with appropriate concentrations is a promising candidate applied for 2.7 µm band optoelectronic devices.