Abstract
Under 980 nm excitation, unusual 3P2 → 3H6 (∼264 nm) and 3P2 → 3F4 (∼309 nm) emissions from Tm3+ ions were observed in hexagonal NaYF4:Yb3+(20%)/Tm 3+(1.5%) microcrystals. In comparison with the strong emissions from 1D2 and 1I6, the emissions from 1G4 and 3H4 almost vanished due to the efficient cross-relaxation of 1G4 + 3H 4 → 3F4 + 1D2 (Tm3+). Double logarithmic plots of the upconversion emission intensity versus the excitation power are neither straight lines nor typical saturation curves. Theoretical analysis indicated that the complicated dependent relationships were mainly caused by phonon-assisted energy transfers and nonradiative relaxation.
Original language | English |
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Pages (from-to) | 11907-11914 |
Number of pages | 8 |
Journal | Optics Express |
Volume | 16 |
Issue number | 16 |
DOIs | |
State | Published - 4 Aug 2008 |
Externally published | Yes |