| Popis: |
Upconversion luminescence of Yb 3+ -doped and Yb 3+ Ho 3+ -codoped oxyfluoride vitroceramics when excited by a diode laser operating at a wavelength of 960 nm is investigated. A strong 479-nm upconversion cooperative radiation luminescence, attributed to the coupled states of Yb 3+ Yb 3+ clusters, is discovered. This result suggests an interesting and effective path to achieve compact blue upconversion luminescence. The presence of holmium in the Yb 3+ Ho 3+ -codoped oxyfluoride vitroceramics substantially reduces intensity of the cooperative upconversion luminescence. |
