In situ calibrated angle between the quantization axis and the propagating direction of the light field for trapping neutral atoms  

作　　者：郭瑞军 何晓东 盛诚 王坤鹏 许鹏 刘敏 王谨 孙晓红 曾勇 詹明生 Rui-Jun Guo;Xiao-Dong He;Cheng Sheng;Kun-Peng Wang;Peng Xu;Min Liu;Jin Wang;Xiao-Hong Sun;Yong Zeng;Ming-Sheng Zhan(Henan Key Laboratory of Laser and Optoelectronic Information,National Center for International Joint Research of Electronic Materials and Systems,School of Electrical and Information Engineering,Zhengzhou University,Zhengzhou 450001,China;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)

机构地区：[1]Henan Key Laboratory of Laser and Optoelectronic Information,National Center for International Joint Research of Electronic Materials and Systems,School of Electrical and Information Engineering,Zhengzhou University,Zhengzhou 450001,China [2]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

出　　处：《Chinese Physics B》2024年第2期318-323,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.12104414,12122412,12104464,and 12104413);the China Postdoctoral Science Foundation(Grant No.2021M702955).

摘　　要：The recently developed magic-intensity trapping technique of neutral atoms efficiently mitigates the detrimental effect of light shifts on atomic qubits and substantially enhances the coherence time. This technique relies on applying a bias magnetic field precisely parallel to the wave vector of a circularly polarized trapping laser field. However, due to the presence of the vector light shift experienced by the trapped atoms, it is challenging to precisely define a parallel magnetic field, especially at a low bias magnetic field strength, for the magic-intensity trapping of85Rb qubits. In this work, we present a method to calibrate the angle between the bias magnetic field and the trapping laser field with the compensating magnetic fields in the other two directions orthogonal to the bias magnetic field direction. Experimentally, with a constantdepth trap and a fixed bias magnetic field, we measure the respective resonant frequencies of the atomic qubits in a linearly polarized trap and a circularly polarized one via the conventional microwave Rabi spectra with different compensating magnetic fields and obtain the corresponding total magnetic fields via the respective resonant frequencies using the Breit–Rabi formula. With known total magnetic fields, the angle is a function of the other two compensating magnetic fields.Finally, the projection value of the angle on either of the directions orthogonal to the bias magnetic field direction can be reduced to 0(4)° by applying specific compensating magnetic fields. The measurement error is mainly attributed to the fluctuation of atomic temperature. Moreover, it also demonstrates that, even for a small angle, the effect is strong enough to cause large decoherence of Rabi oscillation in a magic-intensity trap. Although the compensation method demonstrated here is explored for the magic-intensity trapping technique, it can be applied to a variety of similar precision measurements with trapped neutral atoms.

关 键 词：quantization axis trapping laser ANGLE compensating magnetic fields 

分 类 号：O562[理学—原子与分子物理]