Direct upconversion sensitization luminescence of Er : oxyfluoride glassceramics

This paper researches the direct up-conversion sensitization luminescence o f ErYb codoped oxyfluoride glassceramics (ErYb:FOV) excited by CW 966 nm-di ode laser. It is found that the upconversion mechanism of direct upconversi on sensitization luminescence of YbEr:FOV sample is mainly the energy trans fer between Er3+ and Yb3+ ion but not the step-by-step absorption of single Er3+ ion. This oxyfluoride vitroceramics is forming PbxCd1-xF2 fluoride mi cro-crystallines. And the rare earth ions tend to concentrate in the micro- crystalline, in which there is an intense cluster effect. So upconversion l uminescence is very strong. On the other hand, the log-log variation of up- conversion luminescence intensity with laser power emerges a kind of "typic al saturation phenomenon", in which F-P curve is bended gradually resulting from population exhausting in ground state. We also find a new kind of up- conversion cooperative radiation fluorescence originating from a kind of Co uple State of cluster consisting of two Yb3+ ions in this ErYb:FOV.