4fn−15d→4fn emission of Ce3+, Pr3+, Nd3+, Er3+, and Tm3+ in LiYF4 and YPO4

Abstract

High-resolution $4{f}^{n\ensuremath{-}1}5d\ensuremath{\rightarrow}4{f}^{n}$ emission spectra in the (vacuum) ultraviolet are reported for ${\mathrm{Ce}}^{3+}$, ${\mathrm{Pr}}^{3+}$, ${\mathrm{Nd}}^{3+}$, ${\mathrm{Er}}^{3+}$, and ${\mathrm{Tm}}^{3+}$ in $\mathrm{Li}\mathrm{Y}{\mathrm{F}}_{4}$ and $\mathrm{Y}\mathrm{P}{\mathrm{O}}_{4}$ host lattices. The positions and intensities of the zero-phonon lines are calculated and compared to the high-resolution emission spectra. For the thulium samples gated detection has been used to distinguish between the spin-forbidden and spin-allowed $4{f}^{n\ensuremath{-}1}5d\ensuremath{\rightarrow}4{f}^{n}$ emissions. Luminescence lifetimes for the spin-forbidden $4{f}^{n\ensuremath{-}1}5d\ensuremath{\rightarrow}4{f}^{n}$ emissions are calculated and compared with experimentally observed lifetimes. A good agreement between experiment and theory is found, demonstrating the validity of the model developed for the $4{f}^{n\ensuremath{-}1}5d$ and $4{f}^{n}$ states of lanthanide ions.