Accurate control of magnetic fields is crucial for cold-atom experiments, often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here, we demonstrate precise and flexible control of a static magnetic field by employing a field-programmable gate array and a feedback loop.This setup enables us to maintain exceptionally stable current with a fractional stability of 1 ppm within 30 s.The error signal of the feedback loop exhibited a noise level of 10 -5 A•Hz -1/2 for control bandwidths below 10 kHz.Utilizing this precise magnetic field control system, we investigate the second-order Zeeman shift in the context of cold-atom coherent population-trapping (CPT) clocks.Our analysis reveals the second-order Zeeman coefficient to be 574.21Hz/G 2 , with an uncertainty of 1.36 Hz/G 2 .Consequently, the magnetic field stabilization system we developed allows us to achieve a second-order Zeeman shift below 10 -14 , surpassing the long-term stability of current cold-atom CPT clocks.Accurate control of magnetic fields is crucial for cold-atom experiments, often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here, we demonstrate precise and flexible control of a static magnetic field by employing a field-programmable gate array and a feedback loop.This setup enables us to maintain exceptionally stable current with a fractional stability of 1 ppm within 30 s.The error signal of the feedback loop exhibited a noise level of 10 -5 A•Hz -1/2 for control bandwidths below 10 kHz.Utilizing this precise magnetic field control system, we investigate the second-order Zeeman shift in the context of cold-atom coherent population-trapping (CPT) clocks.Our analysis reveals the second-order Zeeman coefficient to be 574.21Hz/G 2 , with an uncertainty of 1.36 Hz/G 2 .Consequently, the magnetic field stabilization system we developed allows us to achieve a second-order Zeeman shift below 10 -14 , surpassing the long-term stability of current cold-atom CPT clocks.

Chinese Optics LettersJan 1, 20245 citations

Spontaneous coherent trapping of population in the system of atoms + field

A.V. Tajchenachev, A.M. Tumajkin, Valeriy I. Yudin

Bulletin of the Russian Academy of Sciences PhysicsJan 1, 19960 citations

COHERENT TRAPPING OF THE ATOMIC POPULATION

WORLD SCIENTIFIC eBooksJul 1, 19980 citations

High contrast dark resonances in a cold-atom clock probed with counterpropagating circularly polarized beams

Xiaochi Liu, Valeriy I. Yudin, А. В. Тайченачев +2 more

A cold-atom coherent population trapping clock based on σ+−σ− interrogation realized by counter-propagating optical fields of opposite circular polarization is presented. The simultaneous use of σ+ and σ− polarizations prevents atoms from being trapped in the end magnetic sublevels, significantly enhancing the contrast over interrogation with a single circular polarization. Because the system is based on cold atoms and there is very little relaxation, nearly complete dark states are created, and coherent population trapping resonances with maximum contrast are observed. A frequency stability of 1.3×10−11/√τ is achieved, which averages down to 2×10−13 after a 40 000 s integration period.A cold-atom coherent population trapping clock based on σ+−σ− interrogation realized by counter-propagating optical fields of opposite circular polarization is presented. The simultaneous use of σ+ and σ− polarizations prevents atoms from being trapped in the end magnetic sublevels, significantly enhancing the contrast over interrogation with a single circular polarization. Because the system is based on cold atoms and there is very little relaxation, nearly complete dark states are created, and coherent population trapping resonances with maximum contrast are observed. A frequency stability of 1.3×10−11/√τ is achieved, which averages down to 2×10−13 after a 40 000 s integration period.

Applied Physics LettersNov 27, 201744 citations

Cold-atom double- Λ coherent population trapping clock

François-Xavier Esnault, E. Blanshan, Eugene N. Ivanov +3 more

Miniature atomic clocks based on coherent population trapping (CPT) states in thermal atoms are an important component in many field applications, particularly where satellite frequency standards are not accessible. Cold-atom CPT clocks promise improved accuracy and stability over existing commercial technologies. Here we demonstrate a cold-atom CPT clock based on ${}^{87}$ Rb using a high-contrast double-$\ensuremath{\Lambda}$ configuration. Doppler frequency shifts are explained using a simple model and canceled by interrogating the atoms with counterpropagating light beams. We realize a compact cold-atom CPT clock with a fractional frequency stability of $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}{\ensuremath{\tau}}^{\ensuremath{-}1/2}$, thus demonstrating the potential of these devices. We also show that the long-term stability is currently limited by the second-order Zeeman shift to $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at 1000 s.Miniature atomic clocks based on coherent population trapping (CPT) states in thermal atoms are an important component in many field applications, particularly where satellite frequency standards are not accessible. Cold-atom CPT clocks promise improved accuracy and stability over existing commercial technologies. Here we demonstrate a cold-atom CPT clock based on ${}^{87}$Rb using a high-contrast double-$\ensuremath{\Lambda}$ configuration. Doppler frequency shifts are explained using a simple model and canceled by interrogating the atoms with counterpropagating light beams. We realize a compact cold-atom CPT clock with a fractional frequency stability of $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}{\ensuremath{\tau}}^{\ensuremath{-}1/2}$, thus demonstrating the potential of these devices. We also show that the long-term stability is currently limited by the second-order Zeeman shift to $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at 1000 s.

Physical Review AOct 31, 201383 citations

Magnetic Trapping of Neutral Atoms

Harold J. Metcalf, P. van der Straten

Graduate texts in contemporary physicsJan 1, 19993 citations

{}^{87}

Rb using a high-contrast double-$\ensuremath{\Lambda}$ configuration. Doppler frequency shifts are explained using a simple model and canceled by interrogating the atoms with counterpropagating light beams. We realize a compact cold-atom CPT clock with a fractional frequency stability of $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}{\ensuremath{\tau}}^{\ensuremath{-}1/2}$, thus demonstrating the potential of these devices. We also show that the long-term stability is currently limited by the second-order Zeeman shift to $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ at 1000 s.