Preparation and characterization of Er3+-doped TeO2-based oxyhalide glasses

Bulk oxyhalide glasses have been prepared in the TeO2–ZnO–ZnX2 and TeO2–PbO–PbX2 systems (X=Cl, Br, I) and the corresponding glass-forming regions have been determined. Their density and characteristic temperatures were also determined. The glass-forming regions increased in the direction I → Br → Cl and were largest for the zinc-tellurite compositions. For the TeO2–ZnO–ZnCl2 system, compositions with 20 mol% ZnO presented the highest glass-forming ability and had high thermal stability and good infrared transmittance. The progressive replacement of TeO2 by ZnCl2 improved the optical quality of the glasses, as well as their thermal stability, but they became more hygroscopic. Erbium chloride was added to two base glass compositions, 40TeO2–20ZnO–40ZnCl2 and 60TeO2–20ZnO–20ZnCl2 (in mol%) and bulk glass samples could be obtained with additions of up to 10 mol% ErCl3. Photoluminescence measurements of the erbium-doped glasses, at 1.5 μm, showed highest fluorescence intensity for the 60TeO2–20ZnO–20ZnCl2 compositions, especially with 3 mol% ErCl3 with a corresponding metastable level lifetime of ∼6 ms. Higher concentrations of erbium caused a decrease of both properties.