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

Europhysics Letters (EPL)

Picotesla magnetometry with coherent dark states

Markus Stähler, Svenja A. Knappe, C. Affolderbach, W Kemp, R. Wynands

Published May 1, 2001• 104 citations
Publisher

Abstract

We investigate the experimental sensitivity limit of a scalar optical magnetometer based on coherent population trapping on the D 2 line of a thermal cesium vapor. We find the expected strong dependence on averaging time, with a detection limit below 4 pT for integration times longer than 1 s, limited by slow drifts of the cell temperature and of the applied test magnetic-field itself. A detailed noise analysis shows that for shorter averaging times the demonstrated limit of about 12 pT/√Hz is dominated by the frequency noise of the laser source. The magnetometer can be operated for real-time detection in flux densities up to at least milliteslas and is robust enough for application outside the laser laboratory.

DOI
10.1209/epl/i2001-00245-y

Related papers

Experimental realization of coherent dark-state magnetometers

A. Nagel, L Graf, A Naumov +4 more

Coherent population trapping resonances in cesium vapor can be used to determine DC flux densities in the range from 1 mu T to 1 mT with typically 3.10(-5) relative uncertainty. For fields modulated at a few kHz, we find sensitivities of below 10 pT within 0.5 s integration time. From the signal-to-noise ratio the sensitivity can be extrapolated to 500 fT/root Hz.. A quantitative understanding of the lineshape allows to detect DC fields of several nT even when the Zeeman components of the resonance are not resolved.

Europhysics Letters (EPL)•Oct 1, 1998•116 citations

Miniaturized laser magnetometers and clocks

R. Wynands, C. Affolderbach, Leo W. Hollberg +3 more

We have experimentally investigated the potential of narrow coherent population trapping (CPT) resonances for precision applications like magnetometry or atomic frequency standards, using the D lines in thermal Cs or Rb vapor. The magnetometer operates by monitoring the position of the Zeeman-shifted outermost resonance component. The central Zeeman component is well suited for frequency standard applications because its position is shifted by magnetic fields only in second order. We derive the required pair of laser fields form a special diode laser by direct modulation of the injection current. Magneto metric sensitivity down to a picotesla and 10-12 relative instability for a finger-sized clock have been achieved in this way. Use of a magnetic gradiometer allows to cancel fluctuations of ambient magnetic fields to a large degree, making possible sensitive measurements even outside magnetically shielded rooms.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 3, 2002•1 citation

Magnetometry and frequency references with coherent dark states

Sebastián Brandt, A. Nagel, Oliver G. Schmidt +2 more

Summary form only given, as follows.The 30 kHz linewidth and extremely steep dispersion of a coherent dark resonance in a caesium vapor cell allows measurements of magnetic fields to about 10 nT in 0.1 s integration time, limited by stray fields. The narrow resonance should make possible a compact frequency standard. In a preliminary experiment the authors used a coherent dark resonance in a 2 cm long caesium vapor cell to measure magnetic fields with about 10-5 uncertainty. Two diode lasers (852 nm wavelength) were phase-locked onto each other with a 9.2 GHz frequency offset, corresponding to the frequency ground state separation of the two caesium levels. The difference frequency is derived from a stable tunable rf source. Absorption spectrum of the caesium coherent population trapping resonance for linear laser polarizations is illustrated; it is split into seven components by a magnetic field parallel to the laser polarization direction. The width of the individual lines is only 130 kHz due to power broadening. The steep slope of the resonance could be used to lock the frequency of the 9.2 GHz rf source. This would provide a compact frequency reference.

Conference on Precision Electromagnetic Measurements•Dec 24, 2002•0 citations

A high-sensitivity push-pull magnetometer

Breschi, Evelina, Grujić, Zoran D., Knowles, Paul E. +1 more

We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/Hz, using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/Hz.

•Jun 5, 2014•20 citations

A high-sensitivity push-pull magnetometer

E. Breschi, Z. D. Grujić, P. Knowles +1 more

We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/Hz, using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/Hz.

arXiv:1312.3567•Applied Physics Letters•Jan 13, 2014•41 citations

Picotesla magnetometer based on coherently prepared thermal alkali atomic vapors

C. Affolderbach, W. Kemp, Svenja A. Knappe +2 more

Summary form only given. We have experimentally investigated the potential of narrow coherent population trapping (CPT) resonances for precision magnetometry. CPT can be observed in /spl Lambda/ systems where two ground states are coupled to a common excited state by two near-resonant light fields. On resonance, effective formation of long-lived ground state coherences which do not couple in the light fields leads to reduced absorption in the medium ("electromagnetically induced transparency") and thus reduced fluorescence intensity ("dark resonance"). Extremely narrow CPT resonances can be observed when the light fields have fixed phase and frequency difference and time-of-flight broadening is suppressed by the use of a buffer gas, making this type of system a promising candidate for precision applications.

Conference on Lasers and Electro-Optics•Aug 29, 2005•0 citations
We investigate the experimental sensitivity limit of a scalar optical magnetometer based on coherent population trapping on the D 2 line of a thermal cesium vapor. We find the expected strong dependence on averaging time, with a detection limit below 4 pT for integration times longer than 1 s, limited by slow drifts of the cell temperature and of the applied test magnetic-field itself. A detailed noise analysis shows that for shorter averaging times the demonstrated limit of about 12 pT/√Hz is dominated by the frequency noise of the laser source. The magnetometer can be operated for real-time detection in flux densities up to at least milliteslas and is robust enough for application outside the laser laboratory.
Coherent population trapping resonances in cesium vapor can be used to determine DC flux densities in the range from 1 mu T to 1 mT with typically 3.10(-5) relative uncertainty. For fields modulated at a few kHz, we find sensitivities of below 10 pT within 0.5 s integration time. From the signal-to-noise ratio the sensitivity can be extrapolated to 500 fT/root Hz.. A quantitative understanding of the lineshape allows to detect DC fields of several nT even when the Zeeman components of the resonance are not resolved.
We have experimentally investigated the potential of narrow coherent population trapping (CPT) resonances for precision applications like magnetometry or atomic frequency standards, using the D lines in thermal Cs or Rb vapor. The magnetometer operates by monitoring the position of the Zeeman-shifted outermost resonance component. The central Zeeman component is well suited for frequency standard applications because its position is shifted by magnetic fields only in second order. We derive the required pair of laser fields form a special diode laser by direct modulation of the injection current. Magneto metric sensitivity down to a picotesla and 10-12 relative instability for a finger-sized clock have been achieved in this way. Use of a magnetic gradiometer allows to cancel fluctuations of ambient magnetic fields to a large degree, making possible sensitive measurements even outside magnetically shielded rooms.
Summary form only given, as follows.The 30 kHz linewidth and extremely steep dispersion of a coherent dark resonance in a caesium vapor cell allows measurements of magnetic fields to about 10 nT in 0.1 s integration time, limited by stray fields. The narrow resonance should make possible a compact frequency standard. In a preliminary experiment the authors used a coherent dark resonance in a 2 cm long caesium vapor cell to measure magnetic fields with about 10-5 uncertainty. Two diode lasers (852 nm wavelength) were phase-locked onto each other with a 9.2 GHz frequency offset, corresponding to the frequency ground state separation of the two caesium levels. The difference frequency is derived from a stable tunable rf source. Absorption spectrum of the caesium coherent population trapping resonance for linear laser polarizations is illustrated; it is split into seven components by a magnetic field parallel to the laser polarization direction. The width of the individual lines is only 130 kHz due to power broadening. The steep slope of the resonance could be used to lock the frequency of the 9.2 GHz rf source. This would provide a compact frequency reference.
We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/Hz, using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/Hz.
We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/Hz, using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/Hz.
Summary form only given. We have experimentally investigated the potential of narrow coherent population trapping (CPT) resonances for precision magnetometry. CPT can be observed in /spl Lambda/ systems where two ground states are coupled to a common excited state by two near-resonant light fields. On resonance, effective formation of long-lived ground state coherences which do not couple in the light fields leads to reduced absorption in the medium ("electromagnetically induced transparency") and thus reduced fluorescence intensity ("dark resonance"). Extremely narrow CPT resonances can be observed when the light fields have fixed phase and frequency difference and time-of-flight broadening is suppressed by the use of a buffer gas, making this type of system a promising candidate for precision applications.