Europium doping in monoclinic KYb(WO4)2 crystal

We report on a detailed spectroscopic study of Eu3+ ions in the monoclinic KYb(WO4)2 crystal. The polarized room and low-temperature absorption spectra are measured. The maximum σabs corresponding to the 7F1 → 5D1 transition is 1.32×10-20 cm2 at 534.2 nm with a bandwidth of 0.7 nm (for E||Nm). The Stark sub-levels of the excited mulitplets are determined. A Judd-Ofelt analysis is applied to the Eu3+:KYb(WO4)2 crystal to determine the probability of spontaneous transitions, radiative lifetimes and luminescence branching ratios. Within the strong configuration interaction (SCI) approximation, the intensity parameters are Ω2=4.757, Ω4=2.295, Ω6=1.644 [10-20 cm2] and Δf=50160 cm-1. The radiative lifetime of the 5D0 state is 351 µs. The maximum stimulated-emission cross-section corresponding to the 7F1 → 5D1 transition is 1.44×10-20 cm2 at 703.2 nm (for E||Nm). Under UV excitation, the Eu3+:KYb(WO4)2 crystal provides intense red photoluminescence with CIE coordinates, x=0.675, y=0.325.