中国物理B ›› 2022, Vol. 31 ›› Issue (9): 90601-090601.doi: 10.1088/1674-1056/ac5392

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Effective sideband cooling in an ytterbium optical lattice clock

Jin-Qi Wang(王进起)1,2,3, Ang Zhang(张昂)1,2,3, Cong-Cong Tian(田聪聪)1,2,3, Ni Yin(殷妮)1,2,3, Qiang Zhu(朱强)1,2, Bing Wang(王兵)1,2, Zhuan-Xian Xiong(熊转贤)1,2,†, Ling-Xiang He(贺凌翔)1,2,‡, and Bao-Long Lv(吕宝龙)1,2   

  1. 1 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China;
    2 Key Laboratory of Atomic Frequency Standards, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China;
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2021-09-18 修回日期:2022-01-23 接受日期:2022-02-10 出版日期:2022-08-19 发布日期:2022-09-01
  • 通讯作者: Zhuan-Xian Xiong, Ling-Xiang He E-mail:zxxiong@apm.ac.cn;helx@wipm.ac.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. U20A2075).

Effective sideband cooling in an ytterbium optical lattice clock

Jin-Qi Wang(王进起)1,2,3, Ang Zhang(张昂)1,2,3, Cong-Cong Tian(田聪聪)1,2,3, Ni Yin(殷妮)1,2,3, Qiang Zhu(朱强)1,2, Bing Wang(王兵)1,2, Zhuan-Xian Xiong(熊转贤)1,2,†, Ling-Xiang He(贺凌翔)1,2,‡, and Bao-Long Lv(吕宝龙)1,2   

  1. 1 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China;
    2 Key Laboratory of Atomic Frequency Standards, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China;
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-09-18 Revised:2022-01-23 Accepted:2022-02-10 Online:2022-08-19 Published:2022-09-01
  • Contact: Zhuan-Xian Xiong, Ling-Xiang He E-mail:zxxiong@apm.ac.cn;helx@wipm.ac.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. U20A2075).

摘要: Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state. In this work, we demonstrate detailed experimental research on pulsed Raman sideband cooling in a $^{171}$Yb optical lattice clock. A sequence comprised of interleaved 578 nm cooling pulses resonant on the 1st-order red sideband and 1388 nm repumping pulses is carried out to transfer atoms into the motional ground state. We successfully decrease the axial temperature of atoms in the lattice from 6.5 μK to less than 0.8 μK in the trap depth of 24 μK, corresponding to an average axial motional quantum number $\langle n_z\rangle<0.03$. Rabi oscillation spectroscopy is measured to evaluate the effect of sideband cooling on inhomogeneous excitation. The maximum excitation fraction is increased from 0.8 to 0.86, indicating an enhancement in the quantum coherence of the ensemble. Our work will contribute to improving the instability and uncertainty of Yb lattice clocks.

关键词: sideband cooling, ytterbium, optical atomic clock, optical lattice

Abstract: Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state. In this work, we demonstrate detailed experimental research on pulsed Raman sideband cooling in a $^{171}$Yb optical lattice clock. A sequence comprised of interleaved 578 nm cooling pulses resonant on the 1st-order red sideband and 1388 nm repumping pulses is carried out to transfer atoms into the motional ground state. We successfully decrease the axial temperature of atoms in the lattice from 6.5 μK to less than 0.8 μK in the trap depth of 24 μK, corresponding to an average axial motional quantum number $\langle n_z\rangle<0.03$. Rabi oscillation spectroscopy is measured to evaluate the effect of sideband cooling on inhomogeneous excitation. The maximum excitation fraction is increased from 0.8 to 0.86, indicating an enhancement in the quantum coherence of the ensemble. Our work will contribute to improving the instability and uncertainty of Yb lattice clocks.

Key words: sideband cooling, ytterbium, optical atomic clock, optical lattice

中图分类号:  (Metrology)

  • 06.20.-f
06.30.Ft (Time and frequency) 37.10.Jk (Atoms in optical lattices) 37.10.De (Atom cooling methods)