Progress on the^40Ca^+ion optical clock  

作　　者：Baolin Zhang x Yao Huang Huaqing Zhang Yanmei Hao Mengyan Zeng Hua Guan Kelin Gao 张宝林;黄垚;张华青;郝艳梅;曾孟彦;管桦;高克林(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;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;University of Chinese Academy of Sciences,Beijing 100049,China;Center for Cold Atom Physics,Chinese Academy of Sciences,Wuhan 430071,China;Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[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

出　　处：《Chinese Physics B》2020年第7期69-76,共8页中国物理B（英文版）

基　　金：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);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 4^2S1/2-3d ^2D5/2 electric quadrupole transition is reported.By setting the drive frequency to the“magic”frequencyΩ0,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 

分 类 号：TH714.14[机械工程—测试计量技术及仪器]