Spectral properties and theoretical analysis of Dy3+:KGd(WO4)2 crystals in the visible wavelength band

Yellow laser has been widely applied in various fields such as biomedicine, optical communication technology and chip processing. This study focuses on the preparation and characterization of a 3 at.% Dy3+:KGd(WO4)2 crystal. The crystal was grown by the top-seeded solution growth method. The absorption spectrum, excitation spectrum, emission spectrum, and fluorescence decay curve were measured at room temperature, and the fluorescence properties of the crystal in the yellow region were explored. Analysis of the absorption spectrum revealed an absorption cross-section σabs of 4.81 × 10−21 cm2 at 453 nm (E//Y), corresponding to the 6H15/2 → 4I15/2 transition. Utilizing the Judd-Ofelt theory, the J-O intensity parameters Ωt, radiative transition probability, fluorescence branching ratio, and radiative lifetime were calculated. The F-L theory was used to calculate the emission cross-section σem at 575 nm (E//Y), which was found to be 2.43 × 10−20 cm2, along with a fluorescence lifetime τf of 148.5 μs and a fluorescence quantum efficiency of 80.35% for 4F9/2. These findings suggest that Dy3+:KGd(WO4)2 crystal shows significant promise as a yellow laser material, with the potential to contribute to both commercial and scientific fields.