Upconversion (UC) spectra of Ho3/Yb3 codoped Y 2O3, Gd2O3 bulk ceramics were obtained under the excitation of a 976 nm diode laser. Systematic experimental studies, including power dependence, luminescence lifetime, and the intensity ratio σ for the green to NIR emissions, were carried out in order to confirm the UC mechanism of Ho3 ions. Our results demonstrated that the NIR emission was associated with the 5F4/ 5S2→5I7 transition of Ho 3 ions without the contribution of the 5I 4→5I8 transition for Ho 3/Yb3 codoped Y2O3 and Gd 2O3 bulk ceramics. Additionally, population saturation in the 5I7 energy level had been observed in Ho 3/Yb3 codoped Y2O3, Gd 2O3 bulk ceramics. All experimental observations can be well explained by the steady-state rate equations.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics