中国物理B ›› 2020, Vol. 29 ›› Issue (7): 74209-074209.doi: 10.1088/1674-1056/ab9432

所属专题: SPECIAL TOPIC — Ultracold atom and its application in precision measurement

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Progress on the 40Ca+ ion optical clock

Baolin Zhang(张宝林), Yao Huang(黄垚), Huaqing Zhang(张华青), Yanmei Hao(郝艳梅), Mengyan Zeng(曾孟彦), Hua Guan(管桦), Kelin Gao(高克林)   

  1. 1 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences(CAS), Wuhan 430071, China;
    2 Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, 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;
    4 Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China;
    5 Huazhong University of Science and Technology, Wuhan 430074, China
  • 收稿日期:2020-03-16 修回日期:2020-05-18 出版日期:2020-07-05 发布日期:2020-07-05
  • 通讯作者: Hua Guan, Kelin Gao E-mail:guanhua@wipm.ac.cn;klgao@wipm.ac.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant Nos. 2017YFA0304401, 2018YFA0307500, 2017YFA0304404, and 2017YFF0212003), the National Natural Science Foundation of China (Grant Nos. 11622434, 11774388, 11634013, 11934014, and 91736310), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB21030100), the CAS Youth Innovation Promotion Association (Grant Nos. Y201963 and 2018364), and the Science Fund for Distinguished Young Scholars of Hubei Province, China (Grant No. 2017CFA040).

Progress on the 40Ca+ ion optical clock

Baolin Zhang(张宝林)1,2,3, Yao Huang(黄垚)1,2, Huaqing Zhang(张华青)1,2,3, Yanmei Hao(郝艳梅)1,2,3, Mengyan Zeng(曾孟彦)1,2,5, Hua Guan(管桦)1,2, Kelin Gao(高克林)1,2,4   

  1. 1 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences(CAS), Wuhan 430071, China;
    2 Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, 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;
    4 Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China;
    5 Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2020-03-16 Revised:2020-05-18 Online:2020-07-05 Published:2020-07-05
  • Contact: Hua Guan, Kelin Gao E-mail:guanhua@wipm.ac.cn;klgao@wipm.ac.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant Nos. 2017YFA0304401, 2018YFA0307500, 2017YFA0304404, and 2017YFF0212003), the National Natural Science Foundation of China (Grant Nos. 11622434, 11774388, 11634013, 11934014, and 91736310), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB21030100), the CAS Youth Innovation Promotion Association (Grant Nos. Y201963 and 2018364), and the Science Fund for Distinguished Young Scholars of Hubei Province, China (Grant No. 2017CFA040).

摘要: Progress of the 40Ca+ ion optical clock based on the 42S1/2-3d 2D5/2 electric quadrupole transition is reported. By setting the drive frequency to the “magic” frequency Ω0, the frequency uncertainty caused by the scalar Stark shift and second-order Doppler shift induced by micromotion is reduced to the 10-19 level. By precisely measuring the differential static scalar polarizability △α0, the uncertainty due to the blackbody radiation (BBR) shift (coefficient) is reduced to the 10-19 level. With the help of a second-order integrating servo algorithm, the uncertainty due to the servo error is reduced to the 10-18 level. The total fractional uncertainty of the 40Ca+ ion optical clock is then improved to 2.2×10-17, whereas this value is mainly restricted by the uncertainty of the BBR shift due to temperature fluctuations. The state preparation is introduced together with improvements in the pulse sequence, and furthermore, a better signal to noise ratio (SNR) and less dead time are achieved. The clock stability of a single clock is improved to 4.8×10-15/√τ (in seconds).

关键词: 40Ca+ ion optical clocks, “magic” drive frequency, frequency uncertainty, frequency stability

Abstract: Progress of the 40Ca+ ion optical clock based on the 42S1/2-3d 2D5/2 electric quadrupole transition is reported. By setting the drive frequency to the “magic” frequency Ω0, the frequency uncertainty caused by the scalar Stark shift and second-order Doppler shift induced by micromotion is reduced to the 10-19 level. By precisely measuring the differential static scalar polarizability △α0, the uncertainty due to the blackbody radiation (BBR) shift (coefficient) is reduced to the 10-19 level. With the help of a second-order integrating servo algorithm, the uncertainty due to the servo error is reduced to the 10-18 level. The total fractional uncertainty of the 40Ca+ ion optical clock is then improved to 2.2×10-17, whereas this value is mainly restricted by the uncertainty of the BBR shift due to temperature fluctuations. The state preparation is introduced together with improvements in the pulse sequence, and furthermore, a better signal to noise ratio (SNR) and less dead time are achieved. The clock stability of a single clock is improved to 4.8×10-15/√τ (in seconds).

Key words: 40Ca+ ion optical clocks, “magic” drive frequency, frequency uncertainty, frequency stability

中图分类号:  (Laser spectroscopy)

  • 42.62.Fi
37.10.Ty (Ion trapping) 95.55.Sh (Auxiliary and recording instruments; clocks and frequency standards) 06.20.-f (Metrology)