Enhanced yellow fluorescence emission by co-doping Tb3+ into Dy3+:LuPO4 crystal

Abstract

The Dy³⁺:LuPO₄ and Dy³⁺/Tb³⁺:LuPO₄ crystals were successfully synthesized by high temperature solution method. The primary characteristics, including crystal structures, chemical composition, phonon energy, J-O theory, and polarized absorption and emission spectra, were systematically analyzed. The substantial absorption characteristics demonstrated by Dy³⁺:LuPO₄ and Dy³⁺/Tb³⁺:LuPO₄ crystals at 451 nm, featuring absorption FWHMs of 6 nm and cross-sections of 5.96 × 10^-21 cm², suggest the effective compatibility with readily available blue laser diodes for optical pumping. The energy transfer mechanism between Dy³⁺ and Tb³⁺ ions was discussed in detail. Co-doped Tb³⁺ ions not only effectively improve the emission cross-section and fluorescence intensity of Dy³⁺:LuPO₄ crystal at 574 nm, but also reduce the lifetime of the upper laser energy level ⁴F_9/2, which indicates that Tb³⁺ ions can play a better sensitization effect on the emission of Dy³⁺ ions in the yellow wavelength band. The results reveal that Dy³⁺/Tb³⁺:LuPO₄ crystal is a promising yellow laser gain medium.