Realization of Closed-Loop Operation of Optical Lattice Clock Based on ¹⁷¹ Yb

We report the realization of closed-loop operation of an optical lattice clock based on 171 Yb atoms. We interrogate the 1 S 0 → 3 P 0 clock transition using single Rabi pulses of 578 nm laser light. The two π-transitions from m F = ± 1 / 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 × 10 − 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 × 10 − 16 in 7200 s.