Investigation of the 6s6p 3P2-6s7s 3S1 transition of ytterbium atoms with modulation-transfer spectroscopy

We perform the precise measurement of the 6s6p P-3(2)-6s7s S-3(1) transition frequencies of the neutral ytterbium (Yb) atoms by using the modulation transfer spectroscopy. High-resolution dispersive signals of all isotopes except low-abundance Yb-168 (F = 2-F = 1) and Yb-171 (F = 5/2-F = 3/2) are obtained. The frequencies of locked laser are measured using an optical comb, and the obtained results are traced to the absolute transition frequency of the Yb-171 S-1(0)-P-3(0) clock. We measure the isotope shifts relative to Yb-174 and evaluate the systematic shifts. The absolute frequency of the 6s6p P-3(2)-6s7s S-3(1) transition in Yb-174 is determined to be 389260605.8 +/- 3.2 MHz, which has a huge deviation from the existing data in the studies. Based on the obtained transition frequencies, we calculate the hyperfine constants of the P-3(2) and S-3(1) states. This research will provide valuable data for the ytterbium-related experiments and improve the reported transition frequencies with higher precision. Published under an exclusive license by AIP Publishing.