Improvement of Stability of $^{40}$Ca$^{+}$ Optical Clock with State Preparation
Meng-Yan Zeng1,2,3,4, Yao Huang1,2,3, Hu Shao1,2,3,4, Miao Wang1,2,3,4, Hua-Qing Zhang1,2,3,4, Bao-Lin Zhang1,2,3,4, Hua Guan1,2,3, Ke-Lin Gao1,2,3**
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 2Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 3Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 4University of Chinese Academy of Sciences, Beijing 100049
Abstract：Stability is one of most important performances of an atomic clock. Here we describe our recent work on improving the stability of our $^{40}$Ca$^{+}$ optical clock. State preparation is adopted to transfer the ion to the ground-state magnetic sublevel of the clock transition, after the quenching laser transfers the ion to the ground state at each cycle. Using this method, the stability for $^{40}$Ca$^{+}$ optical clock is improved to about $6.3\times 10^{-15}/\sqrt\tau$. Compared with $1.0\times 10^{-14}/\sqrt \tau$ in previous work, the averaging time is decreased to reach a given level of statistical uncertainty in a clock comparison.
2018, Vol. 35 
