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

Physics World

Even colder by laser

Christopher J. Foot

Published Jan 1, 1989• 0 citations
Publisher

Abstract

A Very ingenious technique for laser cooling has enabled a group at the Ecole Normale Superieure (ENS) in Paris to reduce the spread in transverse momentum in an atomic beam to the equivalent of 2μK. By using a fundamentally new approach, Alain Aspect and colleagues (Phys. Rev. Lert. 61 826) have overcome the 'recoil limit'. Previously laser radiation has been used to produce, via absorption and re-emission, a frictional force on atoms to damp their motion. With such techniques the minimum energy for the atoms is approximately the recoil energy from emitting a photon; however, experimentally this limit had not been reached.

DOI
10.1088/2058-7058/2/1/24

Related papers

The coolest atoms yet!

Christopher J. Foot, Andrew M. Steane

New techniques of laser cooling have produced atoms with extremely low temperatures; Christophe Salomon and colleagues at the Ecole Normale Supérieure (ENS), Paris, have just measured caesium atoms with temperatures of only 2.5 ± 0.6 μK, the lowest kinetic temperature yet achieved (1990 Europhys. Lett. 12 683). This impressive experimental achievement is a good example of physics in action since it is the elegant and clear theoretical explanation of the underlying physics of the laser cooling processes, developed at the ENS, which has enabled them to push further than anyone else.

Physics World•Oct 1, 1990•0 citations

Recoil-Limited Laser Cooling of [Formula presented] Atoms near the Fermi Temperature

Takashi Mukaiyama

•Jan 1, 2003•0 citations

Dynamics of laser cooling of atoms below the recoil temperature

I. E. Mazets, Boris G. Matisov

•Nov 1, 1994•0 citations

Experimenters Cool Helium Below Single-Photon Recoil Limit in Three Dimensions

Gloria B. Lubkin

A group at the Ecole Normale Superieure in Paris has placed a helium atom in a state that is going in six directions at once—a very confusing state for an atom. In such a superposition state, also called a dark state, the atom can't absorb light because the absorption amplitudes cancel out by destructive interference. The temperature corresponding to the velocity spread of each of the six wavepackets is a factor of 20 below the so-called recoil limit for laser-cooled atoms. The three-dimensional subrecoil experiment in helium was reported in the 4 December issue of Physical Review Letters by John La wall (now at the National Institute of Standards and Technology in Gaithersburg, Maryland), Si-mone Kulin, Bruno Saubamea, Nick Bigelow, Michèle Leduc and Claude Cohen-Tannoudji.

Physics Today•Jan 1, 1996•3 citations

Recoil-limited laser cooling of 87Sr atoms near the Fermi temperature

Takashi Mukaiyama

•Jan 1, 2003•0 citations

Subrecoil laser cooling and anomalous random walks

François Bardou, Jean‐Philippe Bouchaud, Alain Aspect +1 more

In this chapter, we first recall (in Section 2.1) a few properties of the most usual laser cooling schemes, which involve a friction force. In such standard situations, the motion of the atom in momentum space is a Brownian motion which reaches a steady-state, and the recoil momentum of an atom absorbing or emitting a single photon appears as a natural limit for laser cooling. We then describe in Section 2.2 some completely different laser cooling schemes, based on inhomogeneous random walks in momentum space. These schemes, which are investigated in the present study, allow the ‘recoil limit’ to be overcome. They are associated with non-ergodic statistical processes which never reach a steady-state. Section 2.3 is devoted to a brief survey of various quantum descriptions of subrecoil laser cooling, which become necessary when the ‘recoil limit’ is reached or overcome. The most fruitful one, in the context of this work, is the ‘quantum jump description’ which will allow us in Section 2.4 to replace the microscopic quantum description of subrecoil cooling by a statistical study of a related classical random walk in momentum space. It is this simpler approach that will be used in the subsequent chapters to derive some quantitative analytical predictions, in cases where the quantum microscopic approach is unable to yield precise results, in particular in the limit of very long interaction times, and/or for a momentum space of dimension D higher than 1.

Cambridge University Press eBooks•Jul 2, 2010•4 citations
A Very ingenious technique for laser cooling has enabled a group at the Ecole Normale Superieure (ENS) in Paris to reduce the spread in transverse momentum in an atomic beam to the equivalent of 2μK. By using a fundamentally new approach, Alain Aspect and colleagues (Phys. Rev. Lert. 61 826) have overcome the 'recoil limit'. Previously laser radiation has been used to produce, via absorption and re-emission, a frictional force on atoms to damp their motion. With such techniques the minimum energy for the atoms is approximately the recoil energy from emitting a photon; however, experimentally this limit had not been reached.
New techniques of laser cooling have produced atoms with extremely low temperatures; Christophe Salomon and colleagues at the Ecole Normale Supérieure (ENS), Paris, have just measured caesium atoms with temperatures of only 2.5 ± 0.6 μK, the lowest kinetic temperature yet achieved (1990 Europhys. Lett. 12 683). This impressive experimental achievement is a good example of physics in action since it is the elegant and clear theoretical explanation of the underlying physics of the laser cooling processes, developed at the ENS, which has enabled them to push further than anyone else.
A group at the Ecole Normale Superieure in Paris has placed a helium atom in a state that is going in six directions at once—a very confusing state for an atom. In such a superposition state, also called a dark state, the atom can't absorb light because the absorption amplitudes cancel out by destructive interference. The temperature corresponding to the velocity spread of each of the six wavepackets is a factor of 20 below the so-called recoil limit for laser-cooled atoms. The three-dimensional subrecoil experiment in helium was reported in the 4 December issue of Physical Review Letters by John La wall (now at the National Institute of Standards and Technology in Gaithersburg, Maryland), Si-mone Kulin, Bruno Saubamea, Nick Bigelow, Michèle Leduc and Claude Cohen-Tannoudji.
In this chapter, we first recall (in Section 2.1) a few properties of the most usual laser cooling schemes, which involve a friction force. In such standard situations, the motion of the atom in momentum space is a Brownian motion which reaches a steady-state, and the recoil momentum of an atom absorbing or emitting a single photon appears as a natural limit for laser cooling. We then describe in Section 2.2 some completely different laser cooling schemes, based on inhomogeneous random walks in momentum space. These schemes, which are investigated in the present study, allow the ‘recoil limit’ to be overcome. They are associated with non-ergodic statistical processes which never reach a steady-state. Section 2.3 is devoted to a brief survey of various quantum descriptions of subrecoil laser cooling, which become necessary when the ‘recoil limit’ is reached or overcome. The most fruitful one, in the context of this work, is the ‘quantum jump description’ which will allow us in Section 2.4 to replace the microscopic quantum description of subrecoil cooling by a statistical study of a related classical random walk in momentum space. It is this simpler approach that will be used in the subsequent chapters to derive some quantitative analytical predictions, in cases where the quantum microscopic approach is unable to yield precise results, in particular in the limit of very long interaction times, and/or for a momentum space of dimension D higher than 1.