Benefit of Tb³⁺ ions to the spectral properties of Dy³⁺/Tb³⁺:CaYAlO₄ crystal for use in yellow laser

Single crystals of Dy3+ single-doped and Dy3+/Tb3+ co-doped CaYAlO4 are grown and analyzed. In comparison to Dy3+:CaYAlO4, the absorption cross sections around 453 nm and emission cross section at 582 nm acquired a growth after the incorporation of Tb3+. The fluorescence lifetimes of Dy3+:F-4(9/2) upper and Dy3+:H-6(13/2) lower laser levels for 582 yellow emission fall from 0.293 ms to 0.070 ms-0.285 ms and 0.018 ms, respectively. The fluorescence branching ratios of yellow emission at 582 nm are 49.2% and 50.733% for Dy3+:CaYAlO4 and Dy3+/Tb3+:CaYAlO4 crystals, respectively. Deactivation effect of Tb3+ ions as well as the energy transfer mechanism in Dy3+/Tb3+:CaYAlO4 crystal are discussed in detail, and the temperature dependent spectra of the two crystals are also studied as well. Those results indicate that the introduction of deactivation ion Tb3+ can be beneficial for achieving an enhanced yellow emission in Dy3+/Tb3+:CaYAlO4.