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

Acta Physica Sinica (Overseas Edition)

Study of optical pumping of alkali atomic beam in strong magnetic fields

Ganghua Mei, Huang Gui-long, Xiwen Zhu, Yuan Zhang, Liu Zhi-yuan, Zeng Xiao-yun

Published Nov 1, 1992• 0 citations
Publisher

Abstract

Using rate equation formalism, we got an analytic expression describing the optical pumping of an alkali atomic beam in strong magnetic fields. By comparing with the traditional description in single velocity approximation, the influence of velocity distribution in a practical alkali atomic beam on the pumping effect was quantitatively discussed. It turned out that the rate equation treatment in single velocity approximation might result in an error within twenty percent. Laser optical pumping of 7 Li atomic beam in a strong magnetic field (0.15 T) was experimentally studied, and the results are in agreement with the theory in which the velocity distribution is taken into account.

DOI
10.1088/1004-423x/1/3/003

Related papers

Production of polarized7Li atomic beam in strong magnetic field by optical pumping

Ganghua Mei, Huang Gui-long, Jia‐Min Wang +3 more

The production of a polarized 7 Li atomic beam in a strong magnetic field was experimentally studied by laser optical pumping of a single ground hyperfine F level. It was shown that nearly complete negative and partial positive polarizations of 7 Li atoms could be realized under appropriate conditions by this pumping scheme, which was in agreement with the rate equation calculations. Based on the analyses of transition probabilities, the maximum polarizations for various transitions and light polarizations were given.

Acta Physica Sinica (Overseas Edition)•Jul 1, 1993•0 citations

Optical beam size effects in spin polarized pumping

Xi Zeng, Christine Y. Wang, D. L. Boïko

We have experimentally and theoretically investigate the effect of optical pump beam size on narrowband spin polarized optical pumping of alkali atom vapor. We developed a six-level model describing narrowband spin polarized optical pumping of alkali atoms and applied this model to an atomic vapor cell, accounting for atomic transit time through the optical beam and wall collision effects. Our expression for the wall collision effects is derived from the diffusion model. Overall, we obtained good agreement between theory and experimentally measured relaxation time constants.

European Frequency and Time Forum•Jun 1, 2014•2 citations

Optical pumping effect in absorption imaging of F=1 atomic gases

Sooshin Kim, Sang Won Seo, Heung‐Ryoul Noh +1 more

We report our study of the optical pumping effect in absorption imaging of $^{23}\mathrm{Na}$ atoms in the $F=1$ hyperfine spin states. Solving a set of rate equations for the spin populations in the presence of a probe beam, we obtain an analytic expression for the optical signal of the $F=1$ absorption imaging. Furthermore, we verify the result by measuring the absorption spectra of $^{23}\mathrm{Na}$ Bose-Einstein condensates prepared in various spin states with different probe-beam pulse durations. The analytic result can be used in the quantitative analysis of $F=1$ spinor condensate imaging and readily applied to other alkali-metal atoms with $I=3/2$ nuclear spin such as $^{87}\mathrm{Rb}$.

arXiv:1606.08206•Physical Review A•Aug 22, 2016•5 citations

Influence of skew light propagation on electron spin polarization in an atomic magnetometer

Zekun Wu, Yuchen Jia, Zhen Chai +1 more

Atomics magnetometers achieve remarkable accuracy, applying to production and scientific research. However, their size and bulk components make it difficult to achieve higher accuracy. We investigate the influence of the skew angle of the pump beam on the optical pumping rate in an atomic magnetometer. An analysis based on the Bloch equation is proposed to decrease evaluate optical errors in the process of production and assembly. When the incident angle is non-zero, the pumping rate has a projection in the direction of a static magnetic field. By establishing the pumping rate equation, the pumping rate of each position in the vapor cell in the direction of static magnetic field at different pump light skew angles is calculated in our study. The sensitivity was measured experimentally to demonstrate the simulation results. The results indicate that the optical pumping rate decreases as the amplitude of skew angle and propagation distance increasing which can be evaluated by one-dimensional distribution while the decay rate increases with the rise of the angle. The simulation values of the rubidium pumping rate, obtained with an incident angle of 0.5° , in the center of the vapor cell are reduced by 46%. The sensitivity decreases with the increasing skew angle similar to the attenuation trend of the optical pumping rate but not the same. Our work provides a reference for evaluating the optical error of atomic magnetometer which is useful for miniaturization design.

Optics Frontier Conference (OFS)•Jun 18, 2021•4 citations

Laser cooling at low intensity in a strong magnetic field

P. van der Straten, S-Q. Shang, B. Sheehy +2 more

We have studied theoretically and experimentally the effect of a relatively strong magnetic field on sub-Doppler laser cooling in a one-dimensional optical molasses. We used the operator description of laser cooling with the Larmor precession frequency ${\mathrm{\ensuremath{\omega}}}_{\mathit{Z}}$ being much higher than the optical pumping rate. We found velocity-selective resonances (VSR) in the force at velocities ${\mathit{v}}_{\mathit{r}}$=n${\mathrm{\ensuremath{\omega}}}_{\mathit{Z}}$, with n=0,\ifmmode\pm\else\textpm\fi{}1,\ifmmode\pm\else\textpm\fi{}2 for both the scattering and redistribution force operators. These depend on the relative direction of the magnetic field and the polarization vectors of the light beams. Analytical results for the force on the atom are obtained in two cases that illustrate the effect of the VSR on the force. These formulas are compared with numerical calculations of the force. We also discovered a redistribution mechanism that relies on the gradient of the eigenstates of the light-shift operator, with eigenvalues that are independent of position so that a ``Sisyphus cooling'' picture does not apply. The theory is compared with many experimental results and excellent agreement is found. We believe that all essential features of laser cooling at low intensity are well described by this operator theory.

Physical Review A•May 1, 1993•23 citations

Nonlinear Effects in Optical Pumping of Atoms by a High-Intensity Multimode Gas Laser. General Theory

M. Ducloy

The optical pumping of atoms by a multimode gas laser, in the presence of a magnetic field, is studied theoretically. The atoms are described by their density matrix, which is expanded on an irreducible tensorial set. The atomic relaxation is assumed to be isotropic. In order to avoid the usual perturbation theory, we use the so-called "Broad-Line approximation" (BLA). BLA is valid when the width of the "Bennett hole" created by one laser mode in the velocity distribution of the excited atoms is comparable to the spacing between modes; under these conditions, the atomic response does not depend on the velocity and the multimode laser irradiation is equivalent to a broad-line excitation. For the atomic system, BLA leads to a set of coupled equations which is valid at arbitrary intensities of the laser field and which depends on this field through a unique parameter, $\ensuremath{\gamma}$. This parameter can be understood as a laser-induced transition probability. In this article, we analyze the nonlinear effects which can be deduced from this theory, for any value of the angular momenta involved in the laser transition: Hanle-effect broadening, alignment coupling, saturation resonances on the populations are shown. The exact calculations, valid at arbitrary laser intensities for $J=1\ensuremath{\leftrightarrow}J=0$, $J=1\ensuremath{\leftrightarrow}J=1$, and $J=1\ensuremath{\leftrightarrow}J=2$ transitions, and the corresponding experimental results will be presented in forthcoming papers.

Physical Review A•Oct 1, 1973•83 citations
Using rate equation formalism, we got an analytic expression describing the optical pumping of an alkali atomic beam in strong magnetic fields. By comparing with the traditional description in single velocity approximation, the influence of velocity distribution in a practical alkali atomic beam on the pumping effect was quantitatively discussed. It turned out that the rate equation treatment in single velocity approximation might result in an error within twenty percent. Laser optical pumping of 7 Li atomic beam in a strong magnetic field (0.15 T) was experimentally studied, and the results are in agreement with the theory in which the velocity distribution is taken into account.
The production of a polarized 7 Li atomic beam in a strong magnetic field was experimentally studied by laser optical pumping of a single ground hyperfine F level. It was shown that nearly complete negative and partial positive polarizations of 7 Li atoms could be realized under appropriate conditions by this pumping scheme, which was in agreement with the rate equation calculations. Based on the analyses of transition probabilities, the maximum polarizations for various transitions and light polarizations were given.
We have experimentally and theoretically investigate the effect of optical pump beam size on narrowband spin polarized optical pumping of alkali atom vapor. We developed a six-level model describing narrowband spin polarized optical pumping of alkali atoms and applied this model to an atomic vapor cell, accounting for atomic transit time through the optical beam and wall collision effects. Our expression for the wall collision effects is derived from the diffusion model. Overall, we obtained good agreement between theory and experimentally measured relaxation time constants.
We report our study of the optical pumping effect in absorption imaging of 23Na^{23}\mathrm{Na}23Na atoms in the F=1F=1F=1 hyperfine spin states. Solving a set of rate equations for the spin populations in the presence of a probe beam, we obtain an analytic expression for the optical signal of the F=1F=1F=1 absorption imaging. Furthermore, we verify the result by measuring the absorption spectra of 23Na^{23}\mathrm{Na}23Na Bose-Einstein condensates prepared in various spin states with different probe-beam pulse durations. The analytic result can be used in the quantitative analysis of F=1F=1F=1 spinor condensate imaging and readily applied to other alkali-metal atoms with I=3/2I=3/2I=3/2 nuclear spin such as 87Rb^{87}\mathrm{Rb}87Rb.
Atomics magnetometers achieve remarkable accuracy, applying to production and scientific research. However, their size and bulk components make it difficult to achieve higher accuracy. We investigate the influence of the skew angle of the pump beam on the optical pumping rate in an atomic magnetometer. An analysis based on the Bloch equation is proposed to decrease evaluate optical errors in the process of production and assembly. When the incident angle is non-zero, the pumping rate has a projection in the direction of a static magnetic field. By establishing the pumping rate equation, the pumping rate of each position in the vapor cell in the direction of static magnetic field at different pump light skew angles is calculated in our study. The sensitivity was measured experimentally to demonstrate the simulation results. The results indicate that the optical pumping rate decreases as the amplitude of skew angle and propagation distance increasing which can be evaluated by one-dimensional distribution while the decay rate increases with the rise of the angle. The simulation values of the rubidium pumping rate, obtained with an incident angle of 0.5° , in the center of the vapor cell are reduced by 46%. The sensitivity decreases with the increasing skew angle similar to the attenuation trend of the optical pumping rate but not the same. Our work provides a reference for evaluating the optical error of atomic magnetometer which is useful for miniaturization design.
We have studied theoretically and experimentally the effect of a relatively strong magnetic field on sub-Doppler laser cooling in a one-dimensional optical molasses. We used the operator description of laser cooling with the Larmor precession frequency ${\mathrm{\ensuremath{\omega}}}_{\mathit{Z}}$ being much higher than the optical pumping rate. We found velocity-selective resonances (VSR) in the force at velocities vr{\mathit{v}}_{\mathit{r}}vr​=n${\mathrm{\ensuremath{\omega}}}_{\mathit{Z}}$, with n=0,\ifmmode\pm\else\textpm\fi{}1,\ifmmode\pm\else\textpm\fi{}2 for both the scattering and redistribution force operators. These depend on the relative direction of the magnetic field and the polarization vectors of the light beams. Analytical results for the force on the atom are obtained in two cases that illustrate the effect of the VSR on the force. These formulas are compared with numerical calculations of the force. We also discovered a redistribution mechanism that relies on the gradient of the eigenstates of the light-shift operator, with eigenvalues that are independent of position so that a ``Sisyphus cooling'' picture does not apply. The theory is compared with many experimental results and excellent agreement is found. We believe that all essential features of laser cooling at low intensity are well described by this operator theory.
The optical pumping of atoms by a multimode gas laser, in the presence of a magnetic field, is studied theoretically. The atoms are described by their density matrix, which is expanded on an irreducible tensorial set. The atomic relaxation is assumed to be isotropic. In order to avoid the usual perturbation theory, we use the so-called "Broad-Line approximation" (BLA). BLA is valid when the width of the "Bennett hole" created by one laser mode in the velocity distribution of the excited atoms is comparable to the spacing between modes; under these conditions, the atomic response does not depend on the velocity and the multimode laser irradiation is equivalent to a broad-line excitation. For the atomic system, BLA leads to a set of coupled equations which is valid at arbitrary intensities of the laser field and which depends on this field through a unique parameter, $\ensuremath{\gamma}$. This parameter can be understood as a laser-induced transition probability. In this article, we analyze the nonlinear effects which can be deduced from this theory, for any value of the angular momenta involved in the laser transition: Hanle-effect broadening, alignment coupling, saturation resonances on the populations are shown. The exact calculations, valid at arbitrary laser intensities for $J=1\ensuremath{\leftrightarrow}J=0$, $J=1\ensuremath{\leftrightarrow}J=1$, and $J=1\ensuremath{\leftrightarrow}J=2$ transitions, and the corresponding experimental results will be presented in forthcoming papers.