Ultraviolet and violet upconversion luminescence spectra of holmium-doped Y2O3 were produced under the excitation of a compact continues-wave 532 nm solid-state laser. Emissions around 306, 362, 412, 390 and 428 nm can be assigned to the transitions of 3D3 → 5IJ (J = 8, 7, 6), 5G4 → 5I8 and 5G5 → 5I8, respectively. Power dependence and upconversion dynamics analysis demonstrated that both the energy transfer upconversion (ETU) and the excited state absorption (ESA) processes were involved in the population of 3D3 state via the coupled intermediate states 5S2/5F4. Fluorescence spectra in the visible and infrared ranges showed that 5G4 and 5G5 states were populated by the ESA process from 5I6 and 5I7 states, respectively, while the 5I6 and 5I7 states were radiatively populated from the excited 5S2/ 5F4 states. Upconversion mechanisms have been evaluated based on a rate equation model.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry