Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

AIP Advances

Increasing the length of free-falling path with homogeneous bias field for compact cold atom interferometers by configuring MOT coils

Huankai Zhang, Yaning Wang, Lingxiao Zhu, Qixue Li, Dongyang Xu, Xu Zhang, Shuhua Yan, Jun Jie Yang

Published Sep 1, 2020• 3 citations
Publisher

Abstract

In a cold atom interferometer, a bias magnetic field, usually generated by a solenoid or a set of coils, is used to select specific Raman transitions of atoms in the interference region, and its inhomogeneity leads to a Zeeman-effect-induced error for the measurement. To improve the measurement’s accuracy further, we propose a simple method to compensate for the non-uniformity of the bias field by reversing the direction and tuning the value of the current running through the pair of quadrupole coils used for magneto-optical trap (MOT). To smoothen the field with MOT coils, the current applied should be controlled timely and precisely, which was done with a fast-responding electric circuit we designed and built. We also used Raman spectroscopy to characterize the magnetic field profile without and with our method applied, which shows that the length of the homogeneous field (where the fluctuation of magnetic strength is less than 10%) is expanded from 81.87 mm to 101.64 mm. From our calculations, with the free evolution time T of 30 ms, the quadratic Zeeman-effect-induced phase shift Δϕzeeman can be reduced by 76%, which reduces the quadratic Zeeman-effect-induced error of measured gravity Δgzeeman to a quarter of that without our method applied (from 1.745 mGal to 0.418 mGal). Simulation and experiment prove that this method is effective. This method can also be used in other atom interferometers, especially compact systems.

DOI
10.1063/5.0022637

Related papers

Mapping the absolute magnetic field and evaluating the quadratic Zeeman-effect-induced systematic error in an atom interferometer gravimeter

Qingqing Hu, Christian Freier, Bastian Leykauf +4 more

Precisely evaluating the systematic error induced by the quadratic Zeeman effect is important for developing atom interferometer gravimeters aiming at an accuracy in the $\ensuremath{\mu}\mathrm{Gal}$ regime ($1\ensuremath{\mu}\mathrm{Gal}={10}^{\ensuremath{-}8}\mathrm{m}/{\mathrm{s}}^{2}\ensuremath{\approx}{10}^{\ensuremath{-}9}\mathrm{g}$). This paper reports on the experimental investigation of Raman spectroscopy-based magnetic field measurements and the evaluation of the systematic error in the gravimetric atom interferometer (GAIN) due to quadratic Zeeman effect. We discuss Raman duration and frequency step-size-dependent magnetic field measurement uncertainty, present vector light shift and tensor light shift induced magnetic field measurement offset, and map the absolute magnetic field inside the interferometer chamber of GAIN with an uncertainty of 0.72 nT and a spatial resolution of 12.8 mm. We evaluate the quadratic Zeeman-effect-induced gravity measurement error in GAIN as $2.04\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{Gal}$. The methods shown in this paper are important for precisely mapping the absolute magnetic field in vacuum and reducing the quadratic Zeeman-effect-induced systematic error in Raman transition-based precision measurements, such as atomic interferometer gravimeters.

arXiv:1805.05159•Physical Review A•Sep 20, 2017•38 citations

Optimization design of two-dimensional magneto optical trap field coils for cold atom interferometer

樊鹏格 Fan Pengge, 吴易明 Wu Yiming, 贾森 Jia Sen +1 more

\n\tHigh flux of cold atoms is one of the key technologies to realize high;precision cold atom interferometer. The approach of concatenation of two;dimensional Magnetic Optical Trap (2D;MOT) and three;dimensional Magnetic Optical Trap (3D;MOT) is generally used to obtain high flux of cold atoms. The magnetic field distribution of 2D;MOT is the key influencing factor in this appliance. In this paper, three different(rectangular, race;track and saddle) mathematical models of Anti;Helmholtz coils in 2D;MOT were established to analyze the magnetic field distribution. Then, the magnetic field zero drift and the change of magnetic field gradient caused by the error of eccentricity, coils asymmetry, parallelism and inside diameter asymmetry were analyzed, which were produced in the manufacture and installation process using finite element analysis. Results show that the magnetic field gradient provided by saddle coils is more conducive to produce high flux of cold atoms when eccentricity error is less than 1.14 mm, coils asymmetry error is less than 0.016 A and parallelism error is less than 1.02°. This work may provide theoretical guidance for the design and fabrication of magnetic system of 2D;MOT of cold atom interferometer. © 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.

Infrared and Laser Engineering•Jan 1, 2016•1 citation

Bespoke magnetic field design for a magnetically shielded cold atom interferometer

Peter J. Hobson, Jamie Vovrosh, Ben Stray +10 more

Abstract Quantum sensors based on cold atoms are being developed which produce measurements of unprecedented accuracy. Due to shifts in atomic energy levels, quantum sensors often have stringent requirements on their internal magnetic field environment. Typically, background magnetic fields are attenuated using high permeability magnetic shielding, with the cancelling of residual and introduction of quantisation fields implemented with coils inside the shield. The high permeability shield, however, distorts all magnetic fields, including those generated inside the sensor. Here, we demonstrate a solution by designing multiple coils overlaid on a 3D-printed former to generate three uniform and three constant linear gradient magnetic fields inside the capped cylindrical magnetic shield of a cold atom interferometer. The fields are characterised in-situ and match their desired forms to high accuracy. For example, the uniform transverse field, Bx, deviates by less than 0.2% over more than 40% of the length of the shield. We also map the field directly using the cold atoms and investigate the potential of the coil system to reduce bias from the quadratic Zeeman effect. This coil design technology enables targeted field compensation over large spatial volumes and has the potential to reduce systematic shifts and noise in numerous cold atom systems.

arXiv:2110.04498•Scientific Reports•Jun 22, 2022•18 citations

Rapid extraction of the phase shift of the cold-atom interferometer via phase demodulation

Bing Cheng, 王兆英, 许翱鹏 +2 more

Generally, the phase of the cold-atom interferometer is extracted from the atomic interference fringe, which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T. If mapping the phase shift for each T with a series of measurements, the extraction time is limited by the protocol of each T measurement, and therefore increases dramatically when doing fine mapping with a small step of T. Here we present a new method for rapid extraction of the phase shift via phase demodulation. By using this method, the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. We demonstrate experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T.更多还原

中国物理B：英文版•Jan 1, 2015•0 citations

Optimized design of high-flux 2D magneto-optical trapping

Wei Song, SEN JIA, XIANHUA WANG +1 more

High-precision cold atomic interferometry requires a large flux of cold atomic groups, the length of 2D-MOT largely influences the number of cold atomic clusters in the 3D-MOT flux.The longer the 2D-MOT length, the longer the interaction of the atoms with the light field, so that the trajectory of the atom impinges on the inlet of the differential pump tube so that its divergence is small enough to reach the tube, but the length of 2D-MOT is not the longer,the better.There are two reasons for this: first, higher atomic flux and faster atoms are trapped as the length of 2D-MOT increases, resulting in an increase in the number of collisions between lateral radicals.Second, the average speed in the atomic beam increases.Above an optimum MOT length every increase in length will only add faster atoms to the beam, thus increasing the value for the mean velocity.In summary, choosing the best 2D-MOT length plays a key role in getting the number of cold radicals entering 3D-MOT.In this paper, through mathematical modeling and finite element analysis,2D-MOT race-track anti-Helmholtz coils are numerically calculated.Analyzing the distribution of zero magnetic field for coils of different lengths and zero drift and magnetic field gradient changes caused by the error of asymmetrical coil position , the number of uniform turns and parallelism in the process of processing and assembly.The result provides reliable theoretical guidance for the design and manufacture of the magnetic field system of 2D-MOT high-precision cold-atom interferometers.

International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT)•Jan 18, 2019•0 citations

Rapid extraction of the phase shift of the cold-atom interferometer via phase demodulation

Bing Cheng, Zhaoying Wang, Ao-Peng Xu +2 more

Generally, the phase of the cold-atom interferometer is extracted from the atomic interference fringe, which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T . If mapping the phase shift for each T with a series of measurements, the extraction time is limited by the protocol of each T measurement, and therefore increases dramatically when doing fine mapping with a small step of T . Here we present a new method for rapid extraction of the phase shift via phase demodulation. By using this method, the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. We demonstrate experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T .

Chinese Physics B•Nov 1, 2015•5 citations
In a cold atom interferometer, a bias magnetic field, usually generated by a solenoid or a set of coils, is used to select specific Raman transitions of atoms in the interference region, and its inhomogeneity leads to a Zeeman-effect-induced error for the measurement. To improve the measurement’s accuracy further, we propose a simple method to compensate for the non-uniformity of the bias field by reversing the direction and tuning the value of the current running through the pair of quadrupole coils used for magneto-optical trap (MOT). To smoothen the field with MOT coils, the current applied should be controlled timely and precisely, which was done with a fast-responding electric circuit we designed and built. We also used Raman spectroscopy to characterize the magnetic field profile without and with our method applied, which shows that the length of the homogeneous field (where the fluctuation of magnetic strength is less than 10%) is expanded from 81.87 mm to 101.64 mm. From our calculations, with the free evolution time T of 30 ms, the quadratic Zeeman-effect-induced phase shift Δϕzeeman can be reduced by 76%, which reduces the quadratic Zeeman-effect-induced error of measured gravity Δgzeeman to a quarter of that without our method applied (from 1.745 mGal to 0.418 mGal). Simulation and experiment prove that this method is effective. This method can also be used in other atom interferometers, especially compact systems.
Precisely evaluating the systematic error induced by the quadratic Zeeman effect is important for developing atom interferometer gravimeters aiming at an accuracy in the $\ensuremath{\mu}\mathrm{Gal}$ regime ($1\ensuremath{\mu}\mathrm{Gal}={10}^{\ensuremath{-}8}\mathrm{m}/{\mathrm{s}}^{2}\ensuremath{\approx}{10}^{\ensuremath{-}9}\mathrm{g}$). This paper reports on the experimental investigation of Raman spectroscopy-based magnetic field measurements and the evaluation of the systematic error in the gravimetric atom interferometer (GAIN) due to quadratic Zeeman effect. We discuss Raman duration and frequency step-size-dependent magnetic field measurement uncertainty, present vector light shift and tensor light shift induced magnetic field measurement offset, and map the absolute magnetic field inside the interferometer chamber of GAIN with an uncertainty of 0.72 nT and a spatial resolution of 12.8 mm. We evaluate the quadratic Zeeman-effect-induced gravity measurement error in GAIN as $2.04\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{Gal}$. The methods shown in this paper are important for precisely mapping the absolute magnetic field in vacuum and reducing the quadratic Zeeman-effect-induced systematic error in Raman transition-based precision measurements, such as atomic interferometer gravimeters.
\n\tHigh flux of cold atoms is one of the key technologies to realize high;precision cold atom interferometer. The approach of concatenation of two;dimensional Magnetic Optical Trap (2D;MOT) and three;dimensional Magnetic Optical Trap (3D;MOT) is generally used to obtain high flux of cold atoms. The magnetic field distribution of 2D;MOT is the key influencing factor in this appliance. In this paper, three different(rectangular, race;track and saddle) mathematical models of Anti;Helmholtz coils in 2D;MOT were established to analyze the magnetic field distribution. Then, the magnetic field zero drift and the change of magnetic field gradient caused by the error of eccentricity, coils asymmetry, parallelism and inside diameter asymmetry were analyzed, which were produced in the manufacture and installation process using finite element analysis. Results show that the magnetic field gradient provided by saddle coils is more conducive to produce high flux of cold atoms when eccentricity error is less than 1.14 mm, coils asymmetry error is less than 0.016 A and parallelism error is less than 1.02°. This work may provide theoretical guidance for the design and fabrication of magnetic system of 2D;MOT of cold atom interferometer. © 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.
Abstract Quantum sensors based on cold atoms are being developed which produce measurements of unprecedented accuracy. Due to shifts in atomic energy levels, quantum sensors often have stringent requirements on their internal magnetic field environment. Typically, background magnetic fields are attenuated using high permeability magnetic shielding, with the cancelling of residual and introduction of quantisation fields implemented with coils inside the shield. The high permeability shield, however, distorts all magnetic fields, including those generated inside the sensor. Here, we demonstrate a solution by designing multiple coils overlaid on a 3D-printed former to generate three uniform and three constant linear gradient magnetic fields inside the capped cylindrical magnetic shield of a cold atom interferometer. The fields are characterised in-situ and match their desired forms to high accuracy. For example, the uniform transverse field, Bx, deviates by less than 0.2% over more than 40% of the length of the shield. We also map the field directly using the cold atoms and investigate the potential of the coil system to reduce bias from the quadratic Zeeman effect. This coil design technology enables targeted field compensation over large spatial volumes and has the potential to reduce systematic shifts and noise in numerous cold atom systems.
Generally, the phase of the cold-atom interferometer is extracted from the atomic interference fringe, which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T. If mapping the phase shift for each T with a series of measurements, the extraction time is limited by the protocol of each T measurement, and therefore increases dramatically when doing fine mapping with a small step of T. Here we present a new method for rapid extraction of the phase shift via phase demodulation. By using this method, the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. We demonstrate experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T.更多还原
High-precision cold atomic interferometry requires a large flux of cold atomic groups, the length of 2D-MOT largely influences the number of cold atomic clusters in the 3D-MOT flux.The longer the 2D-MOT length, the longer the interaction of the atoms with the light field, so that the trajectory of the atom impinges on the inlet of the differential pump tube so that its divergence is small enough to reach the tube, but the length of 2D-MOT is not the longer,the better.There are two reasons for this: first, higher atomic flux and faster atoms are trapped as the length of 2D-MOT increases, resulting in an increase in the number of collisions between lateral radicals.Second, the average speed in the atomic beam increases.Above an optimum MOT length every increase in length will only add faster atoms to the beam, thus increasing the value for the mean velocity.In summary, choosing the best 2D-MOT length plays a key role in getting the number of cold radicals entering 3D-MOT.In this paper, through mathematical modeling and finite element analysis,2D-MOT race-track anti-Helmholtz coils are numerically calculated.Analyzing the distribution of zero magnetic field for coils of different lengths and zero drift and magnetic field gradient changes caused by the error of asymmetrical coil position , the number of uniform turns and parallelism in the process of processing and assembly.The result provides reliable theoretical guidance for the design and manufacture of the magnetic field system of 2D-MOT high-precision cold-atom interferometers.
Generally, the phase of the cold-atom interferometer is extracted from the atomic interference fringe, which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T . If mapping the phase shift for each T with a series of measurements, the extraction time is limited by the protocol of each T measurement, and therefore increases dramatically when doing fine mapping with a small step of T . Here we present a new method for rapid extraction of the phase shift via phase demodulation. By using this method, the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. We demonstrate experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T .