Hyperfine constants and line separations for the 1S0-\,3P1 intercombination line in neutral ytterbium with sub-Doppler resolution
Abstract
Optical frequency measurements of the intercombination line (6s2)\,1S0 -(6s6p)\,3P1 in the isotopes of ytterbium are carried out with the use of sub-Doppler fluorescence spectroscopy on an atomic beam. A dispersive signal is generated to which a master laser is locked, while frequency counting of an auxiliary beat signal is performed via a frequency comb referenced to a hydrogen maser. The relative separations between the lines are used to evaluate the 3P1-level magnetic dipole and electric quadrupole constants for the fermionic isotopes. The center of gravity for the 3P1 levels in 171Yb and 173Yb are also evaluated, where we find significant disagreement with previously reported values. These hyperfine constants provide a valuable litmus test for atomic many-body computations in ytterbium.