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

Journal of the Optical Society of America B

Behavior of atoms in a compressed magneto-optical trap

Wolfgang H. Petrich, Michael H. Anderson, J. R. Ensher, Eric Cornell

Published Aug 1, 1994• 156 citations
Publisher

Abstract

We investigate the behavior of a cloud of atoms in a magneto-optical trap, which—after collection—is compressed when the field gradients of the trap magnetic field are increased. We measure sizes and shapes of the atom cloud as a function of laser detuning, magnetic field gradient, and number of trapped atoms. A transient density increase of more than an order of magnitude has been achieved. Moreover, reproducible Gaussian density distributions are observed at large detunings and intermediate magnetic-field gradients, permitting an accurate determination of density.

DOI
10.1364/josab.11.001332

Related papers

Characteristics of single-atom trapping in a magneto-optical trap with a high magnetic-field gradient

Seokchan Yoon, Youngwoon Choi, Sang‐Bum Park +3 more

A quantitative study on characteristics of a magneto-optical trap with a single or a few atoms is presented. A very small number of 85 Rb atoms were trapped in a micron-size magneto-optical trap with a high magnetic-field gradient. In order to find the optimum condition for a single-atom trap, we have investigated how the number of atoms and the size of atomic cloud change as various experimental parameters, such as a magnetic-field gradient and the trapping laser intensity and detuning. The averaged number of atoms was measured very accurately with a calibration procedure based on the single-atom saturation curve of resonance fluorescence. In addition, the number of atoms in a trap could be controlled by suppressing stochastic loading events by means of a real-time active feedback on the magnetic-field gradient.

Journal of Physics Conference Series•Sep 1, 2007•8 citations

Forces acting on magneto-optically trapped atoms

I. Guedes, M. T. de Araújo, D. M. B. P. Milori +3 more

We investigated how the size of ring-shaped clouds of cold, magneto-optically trapped sodium atoms depends on the trapping parameters: magnetic-field gradient and laser intensity, detuning, and misalignment. The experiments were carried out in the low-density regime (N < 106 atoms), and the ring radius was shown to be independent of the number of trapped atoms. The results are explained with a simple model including a coordinate-dependent vortex force and the usual magneto-optical trap forces.

Journal of the Optical Society of America B•Oct 1, 1994•24 citations

Phase-space density in the magneto-optical trap

C. G. Townsend, N. H. Edwards, C. J. Cooper +6 more

We present an investigation of the cesium magneto-optical trap, with particular regard to the best combination of atomic density and temperature that can be produced. Conditions in the trap depend on four independent parameters: the detuning and intensity of the light, the gradient of the magnetic field, and the number of atoms trapped. We have varied all these parameters and measured the temperature and density distribution of the trapped cloud. Both the nonlinear variation with position of the restoring force and the reabsorption of photons scattered in the cloud limit the maximum density, and we present an empirical model that takes this into account. This in turn limits the density in phase space \ensuremath{\rho} (defined as the number of atoms in a box with sides of one thermal de Broglie wavelength). We have observed a maximum \ensuremath{\rho}=(1.5\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$, with a spatial density of about 2\ifmmode\times\else\texttimes\fi{}${10}^{11}$ atoms/${\mathrm{cm}}^{3}$.

Physical Review A•Aug 1, 1995•288 citations

Realization of High Optical Density Rb Magneto-optical Trap

Yanxu Han, Liu Y, Chunhong Zhang +2 more

We report experimental demonstration of a magneto-optical trap (MOT) of Rb atoms with a high optical density. With 2.2-cm-diameter cooling laser beams, we achieve an optical density of nearly 11 for about 2.6 × 10 10 trapped Rb atoms with the beam intensity of about 6.6 mW/cm per beam. The temperature of the cold atoms is about 250 μK. Furthermore, by ramping the magnetic field gradient from 8 G/cm to about 20 G/cm, the atomic cloud in the MOT is compressed and the optical density is up to 16.

Chinese Physics Letters•Feb 1, 2009•3 citations

Stability of Magneto-optical Traps with Large Field Gradients: Limits on the Tight Confinement of Single Atoms

Phil A. Willems, R. A. Boyd, J. L. Bliss +1 more

We report measurements of the stability of magneto-optical traps (MOTs) for neutral atoms in the limit of tight confinement of a single atom. For quadrupole magnetic field gradients at the trap center greater than $\ensuremath{\sim}1\mathrm{kG}/\mathrm{cm}$, we find that stochastic diffusion of atoms out of the trapping volume becomes the dominant particle loss mechanism, ultimately limiting the MOT size to greater than $\ensuremath{\sim}5\ensuremath{\mu}\mathrm{m}$. We measured and modeled the diffusive loss rate as a function of laser power, detuning, and field gradient for trapped cesium atoms. In addition, for as few as two atoms, the collisional loss rates become very high for tightly confined traps, allowing the direct observation of isolated two-body atomic collisions in a MOT.

Physical Review Letters•Mar 3, 1997•22 citations

Characterization of cold atomic cloud in a magneto-optical trap

Poonam Arora, Swatilekha Chowdhury, Ashish Agarwal +2 more

The results of characterization of cold cloud of cesium (Cs) atoms trapped in a magneto-optical trap (MOT) have been presented. The MOT is a part of the Physics package of the Cs Fountain Clock being developed at National Physical Laboratory (NPL), India. The number of atoms, size and temperature of the cloud have been measured and calculated. It is also been investigated how the number of trapped atoms changes with the trapping laser’s beam intensity, detuning and magnetic-field gradient of the trap.

•Sep 1, 2011•0 citations
We investigate the behavior of a cloud of atoms in a magneto-optical trap, which—after collection—is compressed when the field gradients of the trap magnetic field are increased. We measure sizes and shapes of the atom cloud as a function of laser detuning, magnetic field gradient, and number of trapped atoms. A transient density increase of more than an order of magnitude has been achieved. Moreover, reproducible Gaussian density distributions are observed at large detunings and intermediate magnetic-field gradients, permitting an accurate determination of density.
A quantitative study on characteristics of a magneto-optical trap with a single or a few atoms is presented. A very small number of 85 Rb atoms were trapped in a micron-size magneto-optical trap with a high magnetic-field gradient. In order to find the optimum condition for a single-atom trap, we have investigated how the number of atoms and the size of atomic cloud change as various experimental parameters, such as a magnetic-field gradient and the trapping laser intensity and detuning. The averaged number of atoms was measured very accurately with a calibration procedure based on the single-atom saturation curve of resonance fluorescence. In addition, the number of atoms in a trap could be controlled by suppressing stochastic loading events by means of a real-time active feedback on the magnetic-field gradient.
We investigated how the size of ring-shaped clouds of cold, magneto-optically trapped sodium atoms depends on the trapping parameters: magnetic-field gradient and laser intensity, detuning, and misalignment. The experiments were carried out in the low-density regime (N < 106 atoms), and the ring radius was shown to be independent of the number of trapped atoms. The results are explained with a simple model including a coordinate-dependent vortex force and the usual magneto-optical trap forces.
We present an investigation of the cesium magneto-optical trap, with particular regard to the best combination of atomic density and temperature that can be produced. Conditions in the trap depend on four independent parameters: the detuning and intensity of the light, the gradient of the magnetic field, and the number of atoms trapped. We have varied all these parameters and measured the temperature and density distribution of the trapped cloud. Both the nonlinear variation with position of the restoring force and the reabsorption of photons scattered in the cloud limit the maximum density, and we present an empirical model that takes this into account. This in turn limits the density in phase space \ensuremath{\rho} (defined as the number of atoms in a box with sides of one thermal de Broglie wavelength). We have observed a maximum \ensuremath{\rho}=(1.5\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$, with a spatial density of about 2\ifmmode\times\else\texttimes\fi{}1011{10}^{11}1011 atoms/cm3{\mathrm{cm}}^{3}cm3.
We report measurements of the stability of magneto-optical traps (MOTs) for neutral atoms in the limit of tight confinement of a single atom. For quadrupole magnetic field gradients at the trap center greater than $\ensuremath{\sim}1\mathrm{kG}/\mathrm{cm}$, we find that stochastic diffusion of atoms out of the trapping volume becomes the dominant particle loss mechanism, ultimately limiting the MOT size to greater than $\ensuremath{\sim}5\ensuremath{\mu}\mathrm{m}$. We measured and modeled the diffusive loss rate as a function of laser power, detuning, and field gradient for trapped cesium atoms. In addition, for as few as two atoms, the collisional loss rates become very high for tightly confined traps, allowing the direct observation of isolated two-body atomic collisions in a MOT.
The results of characterization of cold cloud of cesium (Cs) atoms trapped in a magneto-optical trap (MOT) have been presented. The MOT is a part of the Physics package of the Cs Fountain Clock being developed at National Physical Laboratory (NPL), India. The number of atoms, size and temperature of the cloud have been measured and calculated. It is also been investigated how the number of trapped atoms changes with the trapping laser’s beam intensity, detuning and magnetic-field gradient of the trap.