中国物理B ›› 2024, Vol. 33 ›› Issue (12): 123701-123701.doi: 10.1088/1674-1056/ad7b00

• • 上一篇    下一篇

Determining the tilt of the Raman laser beam using an optical method for atom gravimeters

Hua-Qing Luo(骆华清), Yao-Yao Xu(徐耀耀)†, Jia-Feng Cui(崔嘉丰)‡, Xiao-Bing Deng(邓小兵), Min-Kang Zhou(周敏康), Xiao-Chun Duan(段小春), and Zhong-Kun Hu(胡忠坤)   

  1. MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
  • 收稿日期:2024-07-31 修回日期:2024-09-12 接受日期:2024-09-14 发布日期:2024-11-12
  • 通讯作者: Yao-Yao Xu E-mail:xuyaoyaoleo@hust.edu.cn
  • 基金资助:
    Project was supported by the National Key Research and Development Program of China (Grant No. 2021YFB3900204).

Determining the tilt of the Raman laser beam using an optical method for atom gravimeters

Hua-Qing Luo(骆华清), Yao-Yao Xu(徐耀耀)†, Jia-Feng Cui(崔嘉丰)‡, Xiao-Bing Deng(邓小兵), Min-Kang Zhou(周敏康), Xiao-Chun Duan(段小春), and Zhong-Kun Hu(胡忠坤)   

  1. MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2024-07-31 Revised:2024-09-12 Accepted:2024-09-14 Published:2024-11-12
  • Contact: Yao-Yao Xu E-mail:xuyaoyaoleo@hust.edu.cn
  • Supported by:
    Project was supported by the National Key Research and Development Program of China (Grant No. 2021YFB3900204).

摘要: The tilt of a Raman laser beam is a major systematic error in precision gravity measurement using atom interferometry. The conventional approach to evaluating this tilt error involves modulating the direction of the Raman laser beam and conducting time-consuming gravity measurements to identify the error minimum. In this work, we demonstrate a method to expediently determine the tilt of the Raman laser beam by transforming the tilt angle measurement into characterization of parallelism, which integrates the optical method of aligning the laser direction, commonly used in freely falling corner-cube gravimeters, into an atom gravimeter. A position-sensing detector (PSD) is utilized to quantitatively characterize the parallelism between the test beam and the reference beam, thus measuring the tilt precisely and rapidly. After carefully positioning the PSD and calibrating the relationship between the distance measured by the PSD and the tilt angle measured by the tiltmeter, we achieved a statistical uncertainty of less than 30 μrad in the tilt measurement. Furthermore, we compared the results obtained through this optical method with those from the conventional tilt modulation method for gravity measurement. The comparison validates that our optical method can achieve tilt determination with an accuracy level of better than 200 μrad, corresponding to a systematic error of 20 μGal in $g$ measurement. This work has practical implications for real-world applications of atom gravimeters.

关键词: atom interferometer, absolute gravimeter, precision measurement, tilt of Raman laser

Abstract: The tilt of a Raman laser beam is a major systematic error in precision gravity measurement using atom interferometry. The conventional approach to evaluating this tilt error involves modulating the direction of the Raman laser beam and conducting time-consuming gravity measurements to identify the error minimum. In this work, we demonstrate a method to expediently determine the tilt of the Raman laser beam by transforming the tilt angle measurement into characterization of parallelism, which integrates the optical method of aligning the laser direction, commonly used in freely falling corner-cube gravimeters, into an atom gravimeter. A position-sensing detector (PSD) is utilized to quantitatively characterize the parallelism between the test beam and the reference beam, thus measuring the tilt precisely and rapidly. After carefully positioning the PSD and calibrating the relationship between the distance measured by the PSD and the tilt angle measured by the tiltmeter, we achieved a statistical uncertainty of less than 30 μrad in the tilt measurement. Furthermore, we compared the results obtained through this optical method with those from the conventional tilt modulation method for gravity measurement. The comparison validates that our optical method can achieve tilt determination with an accuracy level of better than 200 μrad, corresponding to a systematic error of 20 μGal in $g$ measurement. This work has practical implications for real-world applications of atom gravimeters.

Key words: atom interferometer, absolute gravimeter, precision measurement, tilt of Raman laser

中图分类号:  (Atom interferometry techniques)

  • 37.25.+k
04.80.-y (Experimental studies of gravity) 06.30.Gv (Velocity, acceleration, and rotation) 42.79.Fm (Reflectors, beam splitters, and deflectors)