Fig xA Partial energy level diagram
14. Partial energy-level diagram  of Ho3+ illustrating mechanism of fluorescence effects.Figure optionsDownload full-size imageDownload as PowerPoint slide
3.4. Up-conversion luminescence properties and mechanisms
The excitation spectrum of C12A7–1 mol.% Ho3+ is shown in Fig. 15. According to , the ME0328 of range between 790 and 825 nm (centered at 808 nm) can be assigned to 5I8 → 5I5 of Ho3+ ions.