Enhancing 2.7 µm emission of Er3+ in bismuth germanium glasses by introducing BaF2 in the composition

Recently, 2.7 µm lasers have attracted much attention because of their wide applications in remote sensing, and medical laser surgery. The effect of Bi2O3 ↔ BaF2 substitution in the Er3+ doped Bi2O3-GeO2-BaF2 glasses on physical and 2.7 µm emission properties have been studied. Under the excitation of 976 nm LD, an intense and broad 2.7 µm emission originating from the 4I11/2 → 4I13/2 transition of Er3+ was observed. BaF2 was found to enter the glass network as Ba2+ and F−, which may contribute to a reduction in the bridge oxygen content. The 1.55 µm emission was attenuated and the 2.7 µm emission was enhanced due to the combined effect of F− reducing the OH− content of the glass and Ba2+ expanding the distance between Er3+ ions. Furthermore, the peak emission cross-section is calculated to be 12.9 × 10−21 cm2. The Er3+ doped Bi2O3-GeO2-BaF2 glasses show potential as broadband mid-infrared emission gain material.