1Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, wuhan 430071 2University of Chinese Academy of Sciences, Beijing 100049
Abstract:We report the realization of closed-loop operation of an optical lattice clock based on $^{171}$Yb atoms. We interrogate the $^{1}\!S_{0}\rightarrow^{3}\!\!P_{0}$ clock transition using single Rabi pulses of 578 nm laser light. The two $\pi$-transitions from $m_{F}=\pm1/2$ ground states are alternatively interrogated, and the clock laser frequency is locked to the center of the two resonances. The in-loop error signal stability of the clock reaches $3\times10^{-17}$ for an average time of 3500 s. We also perform interleaved operations of the clock with two independent servo loops, and the fractional frequency difference averages down to $2\times10^{-16}$ in 7200 s.