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

High-resolution 4f^n-15d→4fⁿ emission spectra in the (vacuum) ultraviolet are reported for Ce³⁺, Pr³⁺, Nd³⁺, Er³⁺, and Tm³⁺ in LiYF₄ and YPO₄ 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 4f^n-15d→4fⁿ emissions. Luminescence lifetimes for the spin-forbidden 4f^n-15d→4fⁿ 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 4f^n-15d and 4fⁿ states of lanthanide ions.