Removal of hydroxyl routes enhancing 2.85 μm mid-infrared luminescence in oxyfluorotellurite glass with high ZnF2 content

Abstract The near ~3 μm mid-infrared laser demonstrates real and potential applications in many military and civilian areas, but the lack of host materials with nice optical quality and the overlapped vibrations of OH– hamper the emission intensity. To eliminate the OH– absorption, ZnF2 was adopted in Yb3+/Ho3+ codoped binary TeO2-PbF2 glass to partially till totally replace PbF2. The high ZnF2 concentration would raise the glass transition temperature and enhance the thermal stability of matrix, especially enhance the intensity of 2.85 μm mid-infrared luminescence obviously. TeO2-ZnF2 glass with 45.5% ZnF2 original content has high ratio of the strength parameter Ω4/Ω6 (=2.90) and possesses higher spontaneous transition probability (45.25 S−1) along with the larger calculated emission cross section (0.96 × 10−20 cm2) corresponding Ho3+: 5I6 → 5I7 transition. Fourier transmittance of infrared spectra revealed ZnF2 could reduce the OH– concentration in glass substantially, which were favor of 2.85 μm mid-infrared emission. Our results indicated that the use of ZnF2 to effectively remove the hydroxyl groups is an efficacious way to develop near ~3 μm mid-infrared optical glass with high efficient luminescence and thermochemical reliability.