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 Letters

Cooling Neutral Atoms in a Magnetic Trap for Precision Spectroscopy

David E. Pritchard

Published Oct 10, 1983• 414 citations
Publisher

Abstract

A configuration of magnetic fields is exhibited which can harmonically trap paramagnetic particles in a shallow field minimum, superposed on a nearly uniform field which simplifies spectroscopic interactions with the particles. The potential energy of a trapped neutral particle depends on the particle's internal quantum number, as well as its position in the trap, permitting a combined rf-laser optical pumping cycle which can cool particles by a factor of 2 per cycle. Application of these ideas to the trapping of Na atoms is discussed.

DOI
10.1103/physrevlett.51.1336

Related papers

Magnetic trapping of neutral atoms

Thomas H. Bergeman, Harold J. Metcalf

Magnetic trapping of laser-cooled neutral atoms has been demonstrated at NBS and is progressing in other laboratories. Confinement of any object requires exchanging kinetic for potential energy, and for neutral atoms, this necessarily derives from shifts of internal energy levels. This is implemented through the force experienced by the atomic magnetic moment in a carefully designed, highly inhomogeneous field. Since magnetic fields of convenient strength can shift atomic energy levels by only a few gigahertz (temperature ≌ 0.1 K), neutral atom traps are very shallow and must be loaded with very cold atoms. We present some motivations for using magnetic traps and then discuss the constraints and optimal configurations of various arrangements. For example, no trap can be isotropic. Next we discuss both the classical and quantum mechanical motions of trapped atoms. These motions are important for at least two reasons: First, several schemes under study for further cooling depend on knowing the position and velocity of the atoms, as well as the vector field at each point along the orbit. Second, magnetic traps depend on the atomic moment remaining aligned with the field as the atom orbits in the trap, and this precludes rapid motion through a low-field region.

International Laser Science Conference•Jan 1, 1986•0 citations

Magnetic trapping of neutral atoms

Vanderlei Salvador Bagnato, Gregory P. Lafyatis, Alexander G. Martin +2 more

Abstract : The program is to slow, trap and cool neutral atoms. Laser light is used to slow and cool atoms and magnetic forces are used to trap them. Ultimately we hope to be able to trap atoms for days and cool them to temperatures on the order of .000001 K in addition to the interesting scientific and technical challenges involved in trapping and cooling atoms, we hope to open several new lines of investigation with these cooled atoms. Cold trapped atoms constitute a good system for studying collective phenomena such as Bose condensation, low energy - Na and Na - Na, and coherent optical effects (the deBrogile wavelength can exceed the optical wavelength). They also offer opportunities for performing ultra-high resolution spectroscopy and are extremely promising candidates for a new generation of frequency standards.

Massachusetts Inst. of Tech. Report•Jan 1, 1987•0 citations

Electromagnetic Trapping of Neutral Atoms

H. Metcalf, William D. Phillips

Electromagnetic trapping of neutral atoms is a new branch of applied physics that has potential for use in very many areas, including metrology and high-resolution precision spectroscopy. It has the possibility of leading toward the spectroscopic ideal of an isolated atom at rest, available for interaction with electromagnetic field probes. We present an introduction to trapping in both dc magnetic fields and optical fields (laser beams). The basic ideas and fundamental limitations are discussed and the first successful experiments are reviewed.

Metrologia•Jan 1, 1986•11 citations

Laser cooling of magnetically trapped neutral atoms

Kristian Helmerson, Alex Martin, David E. Pritchard

We demonstrate laser Doppler cooling of magnetically trapped neutral atoms. Following the application of one-dimensional optical molasses to a sample of magnetically trapped Na atoms, a substantial reduction has been observed in the linewidths of both laser absorption and rf resonance spectra, indicating cooling of the sample to ∼2 mK. A simple model of the one-dimensional Doppler cooling process of the atoms in the trap is presented and compared with the experimentally observed results.

Journal of the Optical Society of America B•Nov 1, 1992•42 citations

Radiofrequency spectroscopy of trapped neutral atoms

David E. Pritchard, Kristian Helmerson, Min Xiao +1 more

We have recently demonstrated rf resonance experiments on Na atoms contained in a magnetic trap.1,2 Sequential rf pulses with appropriate frequencies were applied to a sample of ~2×1010 Na atoms (confined in an ~100-cm3 volume) to transfer population between the four trapped magnetic substates. The relative populations of the magnetic substates were detected by sending a weak narrowly collimated probe laser beam along the axis of the trap and monitoring the induced fluorescence with a photodiode (placed along the wall of the trap enclosure) located at the longitudinal magnetic field minimum. Hence we are sensitive only to light emanating from the small fraction of atoms near the magnetic field minimum.

Quantum Electronics and Laser Science Conference•Apr 24, 1989•0 citations

Continuous stopping and trapping of neutral atoms

Vanderlei Salvador Bagnato, Gregory P. Lafyatis, Alexander G. Martin +2 more

We have continuously stopped thermal sodium atoms with laser light and loaded them into a 0.1-K deep superconducting magnetic trap. The trap is formed by a local minimum of the magnetic field produced by two superconducting coils and a radially confining octupole field. The atoms are slowed and stopped in two stages: The atoms are first slowed to ~200 m/s using a counterpropagating resonant laser beam and tapered magnetic field to compensate for the changing Doppler shift as the atoms are slowed.1 A second laser beam and tapered magnetic field, actually located within the trap, are used to stop the atoms in the trap. This continuous loading process has allowed us to accumulate up to 1 × 109 trapped atoms, and trapping times of several minutes have been achieved. Our trap has the feature of having a uniform magnetic field at its bottom, opening up the possibility of precision spectroscopy of the trapped atoms. The fluorescence from the trapped atoms has been studied, and they have been cooled to ~1 mK using 1-D optical molasses.

Annual Meeting Optical Society of America•Jan 1, 1987•0 citations
A configuration of magnetic fields is exhibited which can harmonically trap paramagnetic particles in a shallow field minimum, superposed on a nearly uniform field which simplifies spectroscopic interactions with the particles. The potential energy of a trapped neutral particle depends on the particle's internal quantum number, as well as its position in the trap, permitting a combined rf-laser optical pumping cycle which can cool particles by a factor of 2 per cycle. Application of these ideas to the trapping of Na atoms is discussed.
Magnetic trapping of laser-cooled neutral atoms has been demonstrated at NBS and is progressing in other laboratories. Confinement of any object requires exchanging kinetic for potential energy, and for neutral atoms, this necessarily derives from shifts of internal energy levels. This is implemented through the force experienced by the atomic magnetic moment in a carefully designed, highly inhomogeneous field. Since magnetic fields of convenient strength can shift atomic energy levels by only a few gigahertz (temperature ≌ 0.1 K), neutral atom traps are very shallow and must be loaded with very cold atoms. We present some motivations for using magnetic traps and then discuss the constraints and optimal configurations of various arrangements. For example, no trap can be isotropic. Next we discuss both the classical and quantum mechanical motions of trapped atoms. These motions are important for at least two reasons: First, several schemes under study for further cooling depend on knowing the position and velocity of the atoms, as well as the vector field at each point along the orbit. Second, magnetic traps depend on the atomic moment remaining aligned with the field as the atom orbits in the trap, and this precludes rapid motion through a low-field region.
Abstract : The program is to slow, trap and cool neutral atoms. Laser light is used to slow and cool atoms and magnetic forces are used to trap them. Ultimately we hope to be able to trap atoms for days and cool them to temperatures on the order of .000001 K in addition to the interesting scientific and technical challenges involved in trapping and cooling atoms, we hope to open several new lines of investigation with these cooled atoms. Cold trapped atoms constitute a good system for studying collective phenomena such as Bose condensation, low energy - Na and Na - Na, and coherent optical effects (the deBrogile wavelength can exceed the optical wavelength). They also offer opportunities for performing ultra-high resolution spectroscopy and are extremely promising candidates for a new generation of frequency standards.
Electromagnetic trapping of neutral atoms is a new branch of applied physics that has potential for use in very many areas, including metrology and high-resolution precision spectroscopy. It has the possibility of leading toward the spectroscopic ideal of an isolated atom at rest, available for interaction with electromagnetic field probes. We present an introduction to trapping in both dc magnetic fields and optical fields (laser beams). The basic ideas and fundamental limitations are discussed and the first successful experiments are reviewed.
We have recently demonstrated rf resonance experiments on Na atoms contained in a magnetic trap.1,2 Sequential rf pulses with appropriate frequencies were applied to a sample of ~2×1010 Na atoms (confined in an ~100-cm3 volume) to transfer population between the four trapped magnetic substates. The relative populations of the magnetic substates were detected by sending a weak narrowly collimated probe laser beam along the axis of the trap and monitoring the induced fluorescence with a photodiode (placed along the wall of the trap enclosure) located at the longitudinal magnetic field minimum. Hence we are sensitive only to light emanating from the small fraction of atoms near the magnetic field minimum.
We have continuously stopped thermal sodium atoms with laser light and loaded them into a 0.1-K deep superconducting magnetic trap. The trap is formed by a local minimum of the magnetic field produced by two superconducting coils and a radially confining octupole field. The atoms are slowed and stopped in two stages: The atoms are first slowed to ~200 m/s using a counterpropagating resonant laser beam and tapered magnetic field to compensate for the changing Doppler shift as the atoms are slowed.1 A second laser beam and tapered magnetic field, actually located within the trap, are used to stop the atoms in the trap. This continuous loading process has allowed us to accumulate up to 1 × 109 trapped atoms, and trapping times of several minutes have been achieved. Our trap has the feature of having a uniform magnetic field at its bottom, opening up the possibility of precision spectroscopy of the trapped atoms. The fluorescence from the trapped atoms has been studied, and they have been cooled to ~1 mK using 1-D optical molasses.