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

Physical Review Applied

Precisely Mapping the Absolute Magnetic Field in Vacuum by an Optical Ramsey Atom Interferometer

Xiao-Bing Deng, Yaoyao Xu, Xiao‐Chun Duan, Zhong-Kun Hu

Published May 27, 2021• 7 citations
Publisher

Abstract

Atoms in magnetically sensitive sublevels constitute a natural sensor for absolute magnetic field measurements, which are explored here to form an optical Ramsey interferometer for determining the magnetic field distribution. An optical Ramsey atom interferometer provides a convenient way to map a magnetic field in vacuum. In comparison with the often used Raman spectroscopy method, a Ramsey interferometer can not only improve the sensitivity, but also dramatically suppress the contribution of the ac Stark effect. Furthermore, in this work, the magnetically sensitive atoms are velocity-selected, which improves the spatial resolution for the magnetometer as well as the contrast of the Ramsey fringes. A short-term sensitivity of $1.4\phantom{\rule{0.2em}{0ex}}{\mathrm{nT/Hz}}^{1/2}$ for magnetic field measurement is finally achieved even with an interrogation time as short as $500\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{s}$. The presented approach for absolute magnetic field measurement is expected to find wide applications in atom-interferometry-based precision measurements.

DOI
10.1103/physrevapplied.15.054062

Related papers

Precision Magnetic Field Sensing with Dual Multi-Wave Atom Interferometer

Wenhua Yan, Xudong Ren, Min-Kang Zhou +1 more

Precision magnetic field measurement is widely used for practical applications, fundamental research, and medical purposes, etc. We propose a novel quantum magnetometer based on atoms' multi-wave (3-wave and 5-wave) Ramsey interference. Our design features high phase sensitivity and can be applied to in situ measurements of the magnetic field inside vacuum chambers. The final state detection is designed to be achieved by Raman's two-photon transition. The analytical solution for applicable interference fringe is presented. Fringe contrast decay due to atom temperature and magnetic field gradient is simulated to estimate reasonable experimental conditions. Sensitivity functions for phase noise and magnetic field noise in a multi-wave system are derived to estimate the noise level required to reach the expected resolution. The validity of the model, dual-channel features on bias estimation, and the quasi-non-destructive detection feature are discussed.

Sensors•Dec 24, 2022•4 citations

Precisely mapping the magnetic field gradient in vacuum with an atom interferometer

Min-Kang Zhou, Zhong-Kun Hu, Xiao‐Chun Duan +3 more

The magnetic field gradient has been measured with an atom interferometer using the magnetic sublevels of $^{87}\mathrm{Rb}$ atoms. The Doppler-insensitive measurement effectively eliminates the contribution from gravity and background vibration noise, and the differential measurement also can reject some systematic errors. A resolution of $300$ pT/mm has been demonstrated with a $90$-s integration time and a spatial resolution of $1.4$ mm. The gradiometer was then used to measure the magnetic field gradient in an ultrahigh-vacuum environment. The technique will also be very useful to subtract the systematic error arising from the magnetic field inhomogeneity in precision atom-interferometry experiments, such as gravity measurement.

Physical Review A•Dec 10, 2010•61 citations

Magnetic field sensing based on phase Ramsey interferometry with Bose condensed 87Rb atomic gases

Jiatao WU, Ruihuan Fang, Chengyin Han +6 more

Magnetic field sensing utilizing Bose-condensed atomic gases can achieve both high sensitivity and spatial resolution. Employing two-photon transitions from F=1, mF=1→F=2, mF=-1 (F is the quantum number of total atomic angular momentum, mF is the magnetic quantum number of F level) of Bose-condensed 87Rb atomic gases in one-dimensional optical lattice, the precision magnetic field measurement with phase Ramsey interference has been demonstrated. Utilizing single-photon transitions from F=1, mF=1→F=2, mF=0 of Bose-condensed 87Rb atomic gases in a crossed optical dipole trap, we experimentally study frequency domain Ramsey interference, time domain Ramsey interference, and phase domain Ramsey interference. Based on phase Ramsey interference, the sensitivity and spatial resolution of static magnetic field measurement are evaluated. The comparison of these three typical Ramsey interferences reveals that phase Ramsey interference can effectively avoid the fringe distortion in frequency-domain interference and the decoherence effects in time-domain interference, thereby improving the sensitivity and accuracy of the static magnetic field measurement. Utilizing Bose-condensed 87Rb atomic gases with the volume of 1.31±0.03×10-9 cm3 in an unshielded environment, a sensitivity of 130 nT/Hz for static magnetic fields can be achieved. By reducing the preparation time of the atomic gases and increasing the signal interrogation time, the sensitivity has the potential to be further improved.

JOURNAL OF SHENZHEN UNIVERSITY SCIENCE AND ENGINEERING•Sep 1, 2024•0 citations

Unambiguous measurement in an unshielded microscale magnetometer with sensitivity below 1 pT/rHz

Hamish A. M. Taylor, Christopher C. Bounds, Alex Tritt +1 more

Cold atom magnetometers exploit a dense ensemble of quanta with long coherence times to realise leading sensitivity on the micrometer scale. Configured as a Ramsey interferometer, a cold atom sensor can approach atom shot-noise limited precision but suffers from fringe ambiguity, producing gross errors when the field falls outside a narrow predefined range. We describe how Hilbert-demodulated optical magnetometry can be realised on cold atom sensors to provide field measurements both precise and unambiguous. Continuous reconstruction of the Larmor phase allows us to determine the dc magnetic field unambiguously in an unshielded environment, as well as measure ac variation of the field, in a single shot. The ac measurement allows us to characterize, and then neutralise, line-synchronous magnetic interference, extending reconstruction times. Using $1.6 \times 10^6$ $^{87}$Rb atoms in a volume of $(68 \,\mathrm{μm})^3$, we measure a test field to be $ 86.0121261(4) \; \mathrm{μT}$ in a single shot, achieving dc sensitivity of 380 fT in a duration of 1000 ms. Our results demonstrate that Hilbert-demodulated optical readout yields metrologically-significant sensitivity without the fringe ambiguity inherent to Ramsey interferometry.

arXiv:2309.11825•Sep 21, 2023•0 citations

Interferometry using magnetic sensitive states

Saeed Hamzeloui

Atomic interferometry is a very sensitive technique in precision measurements. In this PhD work we explore ways to improve certain aspects of atomic interfer- ometry. We show that there are some advantages on using magnetic sensitive states. We introduce the required infrastructures to implement Ramsey type interferometry on particular transitions. Using a Magneto Optical Trap (MOT) which is the main prerequisite, the atoms are trapped and cooled. The trapping procedure with the MOT requires ingredients such as lasers, the homogeneous and inhomogeneous magnetic fields, the chamber containing the sample, the vacuum system and the detection part (see Chapter 2). At the beginning of my PhD, this facility for trapping the rubidium atoms was available. Later on we upgraded the vacuum system. During this PhD work we could further cool down the trapped sample thanks to the optical molasses technique. We maintain the atoms at temperatures typically below some tenths of micro Kelvin. The coherent manipulation of the atoms is the significant part of this thesis since we aim to do atomic interferometry. Using radiations in microwave domain, it is feasible to couple any two states and do the Rabi oscillations between the hyperfine and Zeeman levels.\nMy first work as a PhD student was to contribute in the Dual Isotope MOT (DIMOT) experiment (see Chapter 3). The idea was to trap both isotopes of rubidium simultaneously by using only single laser and an Electro-Optical Modulator (EOM). This work introduces huge simplifications on the optical part and is extendable to trap more isotopes at the same time. The experiment has the optical and RF parts and my contribution was to complete the RF part.\nStarting all the atoms at the particular initial point for the interferometry takes us some considerable time to be sure that we correctly transfer the atomic population into the desired state (see the discussion in Chapter 4). From that point we focused on two transitions to use the Ramsey type interferometer. Each of these two transitions have an optimum operating point in order to be far from the magnetic field fluctuations since the interferometers are quite sensitive to the field perturbations sensed from the environment. At the end we aim to combine these two transitions of interest to make a dual interferometer (see Chapter 6). The idea is to obtain the minimum magnetic sensitivity at a tunable magnetic field by changing the fraction of atoms in each interferometer. The dual interferometer may be useful in applications where low magnetic sensitivity is required at a particular magnetic field.

•Jan 1, 2016•0 citations

Unambiguous measurement in an unshielded microscale magnetometer with sensitivity below 1 pT / Hz

Hamish A. M. Taylor, Christopher C. Bounds, Alex Tritt +1 more

Cold-atom magnetometers exploit a dense ensemble of quanta with long coherence times to realize leading sensitivity on the micrometer scale. Configured as a Ramsey interferometer, a cold-atom sensor can approach atom shot-noise limited precision but suffers from fringe ambiguity, producing gross errors when the field falls outside a narrow predefined range. We describe how Hilbert-demodulated optical magnetometry can be realized on cold-atom sensors to provide field measurements both precise and unambiguous. Continuous reconstruction of the Larmor phase allows us to determine the dc magnetic field unambiguously in an unshielded environment, as well as measure ac variation of the field, in a single shot. The ac measurement allows us to characterize, and then neutralize, line-synchronous magnetic interference, extending reconstruction times. Using $1.6\ifmmode\times\else\texttimes\fi{}{10}^{6}{\phantom{\rule{0.2em}{0ex}}}^{87}\mathrm{Rb}$ atoms in a volume of $(68\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}\mathrm{m}{)}^{3}$, we measure a test field to be $86.0121261(4)\phantom{\rule{0.1em}{0ex}}\phantom{\rule{0.1em}{0ex}}\text{\ensuremath{\mu}}\mathrm{T}$ in a single shot, achieving dc sensitivity of $380\phantom{\rule{0.1em}{0ex}}\mathrm{fT}$ in a duration of $1000\phantom{\rule{0.1em}{0ex}}\mathrm{ms}$. Our results demonstrate that Hilbert-demodulated optical readout yields metrologically significant sensitivity without the fringe ambiguity inherent to Ramsey interferometry.

Physical Review Applied•Aug 16, 2024•8 citations
Atoms in magnetically sensitive sublevels constitute a natural sensor for absolute magnetic field measurements, which are explored here to form an optical Ramsey interferometer for determining the magnetic field distribution. An optical Ramsey atom interferometer provides a convenient way to map a magnetic field in vacuum. In comparison with the often used Raman spectroscopy method, a Ramsey interferometer can not only improve the sensitivity, but also dramatically suppress the contribution of the ac Stark effect. Furthermore, in this work, the magnetically sensitive atoms are velocity-selected, which improves the spatial resolution for the magnetometer as well as the contrast of the Ramsey fringes. A short-term sensitivity of 1.4nT/Hz1/21.4\phantom{\rule{0.2em}{0ex}}{\mathrm{nT/Hz}}^{1/2}1.4nT/Hz1/2 for magnetic field measurement is finally achieved even with an interrogation time as short as 500\ensuremathμs500\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{s}500\ensuremathμs. The presented approach for absolute magnetic field measurement is expected to find wide applications in atom-interferometry-based precision measurements.
Precision magnetic field measurement is widely used for practical applications, fundamental research, and medical purposes, etc. We propose a novel quantum magnetometer based on atoms' multi-wave (3-wave and 5-wave) Ramsey interference. Our design features high phase sensitivity and can be applied to in situ measurements of the magnetic field inside vacuum chambers. The final state detection is designed to be achieved by Raman's two-photon transition. The analytical solution for applicable interference fringe is presented. Fringe contrast decay due to atom temperature and magnetic field gradient is simulated to estimate reasonable experimental conditions. Sensitivity functions for phase noise and magnetic field noise in a multi-wave system are derived to estimate the noise level required to reach the expected resolution. The validity of the model, dual-channel features on bias estimation, and the quasi-non-destructive detection feature are discussed.
The magnetic field gradient has been measured with an atom interferometer using the magnetic sublevels of 87Rb^{87}\mathrm{Rb}87Rb atoms. The Doppler-insensitive measurement effectively eliminates the contribution from gravity and background vibration noise, and the differential measurement also can reject some systematic errors. A resolution of 300300300 pT/mm has been demonstrated with a 909090-s integration time and a spatial resolution of 1.41.41.4 mm. The gradiometer was then used to measure the magnetic field gradient in an ultrahigh-vacuum environment. The technique will also be very useful to subtract the systematic error arising from the magnetic field inhomogeneity in precision atom-interferometry experiments, such as gravity measurement.
Magnetic field sensing utilizing Bose-condensed atomic gases can achieve both high sensitivity and spatial resolution. Employing two-photon transitions from F=1, mF=1→F=2, mF=-1 (F is the quantum number of total atomic angular momentum, mF is the magnetic quantum number of F level) of Bose-condensed 87Rb atomic gases in one-dimensional optical lattice, the precision magnetic field measurement with phase Ramsey interference has been demonstrated. Utilizing single-photon transitions from F=1, mF=1→F=2, mF=0 of Bose-condensed 87Rb atomic gases in a crossed optical dipole trap, we experimentally study frequency domain Ramsey interference, time domain Ramsey interference, and phase domain Ramsey interference. Based on phase Ramsey interference, the sensitivity and spatial resolution of static magnetic field measurement are evaluated. The comparison of these three typical Ramsey interferences reveals that phase Ramsey interference can effectively avoid the fringe distortion in frequency-domain interference and the decoherence effects in time-domain interference, thereby improving the sensitivity and accuracy of the static magnetic field measurement. Utilizing Bose-condensed 87Rb atomic gases with the volume of 1.31±0.03×10-9 cm3 in an unshielded environment, a sensitivity of 130 nT/Hz for static magnetic fields can be achieved. By reducing the preparation time of the atomic gases and increasing the signal interrogation time, the sensitivity has the potential to be further improved.
Cold atom magnetometers exploit a dense ensemble of quanta with long coherence times to realise leading sensitivity on the micrometer scale. Configured as a Ramsey interferometer, a cold atom sensor can approach atom shot-noise limited precision but suffers from fringe ambiguity, producing gross errors when the field falls outside a narrow predefined range. We describe how Hilbert-demodulated optical magnetometry can be realised on cold atom sensors to provide field measurements both precise and unambiguous. Continuous reconstruction of the Larmor phase allows us to determine the dc magnetic field unambiguously in an unshielded environment, as well as measure ac variation of the field, in a single shot. The ac measurement allows us to characterize, and then neutralise, line-synchronous magnetic interference, extending reconstruction times. Using 1.6×1061.6 \times 10^61.6×106 87^{87}87Rb atoms in a volume of (68 μm)3(68 \,\mathrm{μm})^3(68μm)3, we measure a test field to be $ 86.0121261(4) \; \mathrm{μT}$ in a single shot, achieving dc sensitivity of 380 fT in a duration of 1000 ms. Our results demonstrate that Hilbert-demodulated optical readout yields metrologically-significant sensitivity without the fringe ambiguity inherent to Ramsey interferometry.
Atomic interferometry is a very sensitive technique in precision measurements. In this PhD work we explore ways to improve certain aspects of atomic interfer- ometry. We show that there are some advantages on using magnetic sensitive states. We introduce the required infrastructures to implement Ramsey type interferometry on particular transitions. Using a Magneto Optical Trap (MOT) which is the main prerequisite, the atoms are trapped and cooled. The trapping procedure with the MOT requires ingredients such as lasers, the homogeneous and inhomogeneous magnetic fields, the chamber containing the sample, the vacuum system and the detection part (see Chapter 2). At the beginning of my PhD, this facility for trapping the rubidium atoms was available. Later on we upgraded the vacuum system. During this PhD work we could further cool down the trapped sample thanks to the optical molasses technique. We maintain the atoms at temperatures typically below some tenths of micro Kelvin. The coherent manipulation of the atoms is the significant part of this thesis since we aim to do atomic interferometry. Using radiations in microwave domain, it is feasible to couple any two states and do the Rabi oscillations between the hyperfine and Zeeman levels.\nMy first work as a PhD student was to contribute in the Dual Isotope MOT (DIMOT) experiment (see Chapter 3). The idea was to trap both isotopes of rubidium simultaneously by using only single laser and an Electro-Optical Modulator (EOM). This work introduces huge simplifications on the optical part and is extendable to trap more isotopes at the same time. The experiment has the optical and RF parts and my contribution was to complete the RF part.\nStarting all the atoms at the particular initial point for the interferometry takes us some considerable time to be sure that we correctly transfer the atomic population into the desired state (see the discussion in Chapter 4). From that point we focused on two transitions to use the Ramsey type interferometer. Each of these two transitions have an optimum operating point in order to be far from the magnetic field fluctuations since the interferometers are quite sensitive to the field perturbations sensed from the environment. At the end we aim to combine these two transitions of interest to make a dual interferometer (see Chapter 6). The idea is to obtain the minimum magnetic sensitivity at a tunable magnetic field by changing the fraction of atoms in each interferometer. The dual interferometer may be useful in applications where low magnetic sensitivity is required at a particular magnetic field.
Cold-atom magnetometers exploit a dense ensemble of quanta with long coherence times to realize leading sensitivity on the micrometer scale. Configured as a Ramsey interferometer, a cold-atom sensor can approach atom shot-noise limited precision but suffers from fringe ambiguity, producing gross errors when the field falls outside a narrow predefined range. We describe how Hilbert-demodulated optical magnetometry can be realized on cold-atom sensors to provide field measurements both precise and unambiguous. Continuous reconstruction of the Larmor phase allows us to determine the dc magnetic field unambiguously in an unshielded environment, as well as measure ac variation of the field, in a single shot. The ac measurement allows us to characterize, and then neutralize, line-synchronous magnetic interference, extending reconstruction times. Using $1.6\ifmmode\times\else\texttimes\fi{}{10}^{6}{\phantom{\rule{0.2em}{0ex}}}^{87}\mathrm{Rb}$ atoms in a volume of $(68\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}\mathrm{m}{)}^{3}$, we measure a test field to be $86.0121261(4)\phantom{\rule{0.1em}{0ex}}\phantom{\rule{0.1em}{0ex}}\text{\ensuremath{\mu}}\mathrm{T}$ in a single shot, achieving dc sensitivity of 380fT380\phantom{\rule{0.1em}{0ex}}\mathrm{fT}380fT in a duration of 1000ms1000\phantom{\rule{0.1em}{0ex}}\mathrm{ms}1000ms. Our results demonstrate that Hilbert-demodulated optical readout yields metrologically significant sensitivity without the fringe ambiguity inherent to Ramsey interferometry.