Absolute frequency measurement of the 6s6p1P1-6s7s1S0 transition of Yb 174 in a Yb hollow-cathode lamp

We report absolute frequency measurement of the 6s6p1P1-6s7s1S0 transition at 1077.3 nm of Yb174 in a hollow-cathode lamp (HCL). The frequency of coupling laser was stabilized to the 6s21S0-6s6p1P1 transition at 398.9 nm using an Yb atomic beam, and the coupling laser beam was then overlapped with the counterpropagating probe laser beam at 1077.3 nm in the Yb HCL to obtain a Doppler-free signal of laser-induced birefringence for the frequency stabilization of the probe laser. Systematic frequency shifts of both transitions as a function of the discharge current of the Yb HCL were analyzed using an Yb-doped fiber laser frequency comb. The absolute frequency of the 6s6p1P1-6s7s1S0 transition was measured to be 278 281 521.4(7.2) MHz, and from the published frequency of the transition, the absolute frequency of the 6s21S0-6s7s1S0 two-photon transition at 291.1 nm was determined to be 1 029 807 509.2(7.2) MHz with the relative standard uncertainty of 7.0×10-9.