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

Laser cooling of atoms below the single-photon classical limit

Vladimir G. Minogin, M. A. Ol'shanyi, S. U. Shulga

Published Nov 1, 1989• 11 citations
Publisher

Abstract

We describe a new mechanism for the laser cooling of atoms. The mechanism is based on the damping of the motion of three-level atoms by laser light pressure under the condition of coherent atomic population trapping. Because of the action of this mechanism, three-level atoms can be cooled below the temperature of the single-photon classical limit, Tγ = ℏγ/kB, to a temperature corresponding to the recoil energy, TR = ℏ2k2/2MkB. It is probable that the mechanism described has a part in the recently observed laser cooling of sodium atoms below the temperature ℏγ/ kB.

DOI
10.1364/josab.6.002108

Related papers

Laser cooling below a photon recoil with three-level atoms

Mark A. Kasevich, Steven Chu

We demonstrate a new cooling technique which is used to cool sodium atoms in one dimension to an effective temperature of 100 nK, less than 1/10 of the single photon recoil temperature ${\mathit{k}}_{\mathit{B}}$${\mathit{T}}_{\mathrm{rec}}$=(\ensuremath{\Elzxh}k${)}^{2}$/2M.

Physical Review Letters•Sep 21, 1992•449 citations

Temperature limits in laser cooling of free atoms with three-level transitions

Flávio C. Cruz, Michael Lee Sundheimer, Wictor C. Magno

Summary form only given. We consider laser cooling of free atoms with simultaneous two-color excitation of three-level cascade transitions [1], [2], [3], [4], [5], [6] finding theoretically that temperatures below the Doppler limits associated with each one of the individual transitions are obtained. We use standard laser cooling analysis [7], [8] and the dressed state picture in order to identify different cooling regions, and determining optimum parameters for guiding further experiments. These new “sub-Doppler” limits are reached at the two-photon resonance where a significant increase of the damping coefficient and decrease of the diffusion take place. In the dressed state picture, this point corresponds to a crossing of the narrow and a (partially) dark state.Figure 1 shows a plot of temperature (normalized to the Doppler limit for cooling only on the lower transition) as function of single-photon detunings, for the 1S0-1P1-1D2 transition of Magnesium, in which the lower 1S0-1P1 transition is the usual cooling one (λ1 = 2πc/ω1 = 285 nm, λ2 = 2πc/ω2 = 881 nm, γ1 = 2π 78.8 MHz, γ2 = 2π 2.2 MHz). A minimum temperature of 38 μK is predicted. This temperature is lower than the Doppler temperature of the lower and upper transitions, TD = γ/k = 1.9 mK and 49 μK respectively. Due to the asymmetric absorption profile of the dressed atom, there is a remarkable increase in the damping coefficient (α) associated with the narrow transition, in comparison with the broad transition (two-level cooling). The cooling and damping times, inversely proportional to α, are reduced by the same amount. Since the curve for the diffusion coefficient (D) has the same shape as the curve for the absorption coefficient or the population of the intermediate state, D is also reduced with respect to the broad resonance, We analyze situations previously implemented experimentally in alkaline-Earth atoms using cascade transitions, and also discuss prospects for Aand V-type three-level systems.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•May 1, 2013•0 citations

Laser cooling below the recoil limit by stimulated Raman transitions

Nir Davidson

A technique for cooling atoms in two dimensions to temperatures below the single photon recoil limit k{sub B}T{sub rec} = (hk){sup 2}/2M is demonstrated. This technique combines velocity selection using stimulated Raman transitions and dissipation by spontaneous emission. It is an extension of the one dimensional cooling technique that was demonstrated recently. Experimental results for sodium atoms are presented, and the limits on the minimal cooling temperatures are analyzed. Finally, the possibility of applying the Raman cooling technique to atoms in a dipole trap is discussed.

Bulletin of the American Physical Society•May 1, 1993•0 citations

Laser cooling below the one-photon recoil energy by velocity-selective coherent population trapping: theoretical analysis

Alain Aspect, E. Arimondo, Robin Kaiser +2 more

We present a theoretical analysis of a new one-dimensional laser-cooling scheme that was recently demonstrated on a beam of metastable 4He atoms. Both internal and translational degrees of freedom are treated quantum mechanically. Unlike semiclassical approaches, such a treatment can be applied to situations in which the atomic coherence length is of the same order of or larger than the laser wavelength, which is the case for atoms cooled below the one-photon recoil energy. We introduce families of states that are closed with respect to absorption and stimulated emission, and we establish the generalized optical Bloch equations that are satisfied by the corresponding matrix elements. The existence of velocity-selective trapping states that are linear combinations of states with different internal and translational quantum numbers is demonstrated, and the mechanism of accumulation of atoms in these trapping states by fluorescence cycles is analyzed. From a numerical solution of the generalized optical Bloch equations, we study in detail how the final atomic-momentum distribution depends on the various physical parameters: interaction time, width of the initial distribution, laser detuning, laser power, and imbalance between the two counterpropagating waves. We show that the final temperature decreases when the interaction time increases, so that there is no fundamental limit to the lowest temperature that can be achieved by such a method. Finally, possible extensions of this method to two-dimensional cooling are presented.

Journal of the Optical Society of America B•Nov 1, 1989•293 citations

Three-Dimensional Laser Cooling of Helium Beyond the Single-Photon Recoil Limit

John Lawall, S. A. Kulin, Bruno Saubaméa +3 more

We report the first observation of subrecoil laser cooling in three dimensions, where we use the method of velocity-selective coherent population trapping. We have cooled a cloud of trapped metastable helium atoms to 180 nK, 22 times below the single-photon recoil temperature, with an enhancement in the momentum-space density of 16. We find that the efficiency with which the velocity-selective trap is populated can be augmented by Sisyphus-type frictional forces, while the cooling process is accompanied by the diffusion of atoms to states of very high velocity.

Physical Review Letters•Dec 4, 1995•120 citations

Laser Cooling below the One-Photon Recoil Energy by Velocity-Selective Coherent Population Trapping

Alain Aspect, E. Arimondo, Robin Kaiser +2 more

We present a new laser-cooling scheme based on velocity-selective optical pumping of atoms into a nonabsorbing coherent superposition of states. This method has allowed us to achieve transverse cooling of metastable $^{4}\mathrm{He}$ atoms to a temperature of 2 \ensuremath{\mu}K, lower than both the usual Doppler cooling limit (23 \ensuremath{\mu}K) and the one-photon recoil energy (4 \ensuremath{\mu}K). The corresponding de Broglie wavelength (1.4 \ensuremath{\mu}m) is larger than the atomic-transition optical wavelength.

Physical Review Letters•Aug 15, 1988•865 citations
We describe a new mechanism for the laser cooling of atoms. The mechanism is based on the damping of the motion of three-level atoms by laser light pressure under the condition of coherent atomic population trapping. Because of the action of this mechanism, three-level atoms can be cooled below the temperature of the single-photon classical limit, Tγ = ℏγ/kB, to a temperature corresponding to the recoil energy, TR = ℏ2k2/2MkB. It is probable that the mechanism described has a part in the recently observed laser cooling of sodium atoms below the temperature ℏγ/ kB.
We demonstrate a new cooling technique which is used to cool sodium atoms in one dimension to an effective temperature of 100 nK, less than 1/10 of the single photon recoil temperature kB{\mathit{k}}_{\mathit{B}}kB​Trec{\mathit{T}}_{\mathrm{rec}}Trec​=(\ensuremath{\Elzxh}k)2{)}^{2})2/2M.
Summary form only given. We consider laser cooling of free atoms with simultaneous two-color excitation of three-level cascade transitions [1], [2], [3], [4], [5], [6] finding theoretically that temperatures below the Doppler limits associated with each one of the individual transitions are obtained. We use standard laser cooling analysis [7], [8] and the dressed state picture in order to identify different cooling regions, and determining optimum parameters for guiding further experiments. These new “sub-Doppler” limits are reached at the two-photon resonance where a significant increase of the damping coefficient and decrease of the diffusion take place. In the dressed state picture, this point corresponds to a crossing of the narrow and a (partially) dark state.Figure 1 shows a plot of temperature (normalized to the Doppler limit for cooling only on the lower transition) as function of single-photon detunings, for the 1S0-1P1-1D2 transition of Magnesium, in which the lower 1S0-1P1 transition is the usual cooling one (λ1 = 2πc/ω1 = 285 nm, λ2 = 2πc/ω2 = 881 nm, γ1 = 2π 78.8 MHz, γ2 = 2π 2.2 MHz). A minimum temperature of 38 μK is predicted. This temperature is lower than the Doppler temperature of the lower and upper transitions, TD = γ/k = 1.9 mK and 49 μK respectively. Due to the asymmetric absorption profile of the dressed atom, there is a remarkable increase in the damping coefficient (α) associated with the narrow transition, in comparison with the broad transition (two-level cooling). The cooling and damping times, inversely proportional to α, are reduced by the same amount. Since the curve for the diffusion coefficient (D) has the same shape as the curve for the absorption coefficient or the population of the intermediate state, D is also reduced with respect to the broad resonance, We analyze situations previously implemented experimentally in alkaline-Earth atoms using cascade transitions, and also discuss prospects for Aand V-type three-level systems.
A technique for cooling atoms in two dimensions to temperatures below the single photon recoil limit k{sub B}T{sub rec} = (hk){sup 2}/2M is demonstrated. This technique combines velocity selection using stimulated Raman transitions and dissipation by spontaneous emission. It is an extension of the one dimensional cooling technique that was demonstrated recently. Experimental results for sodium atoms are presented, and the limits on the minimal cooling temperatures are analyzed. Finally, the possibility of applying the Raman cooling technique to atoms in a dipole trap is discussed.
We present a theoretical analysis of a new one-dimensional laser-cooling scheme that was recently demonstrated on a beam of metastable 4He atoms. Both internal and translational degrees of freedom are treated quantum mechanically. Unlike semiclassical approaches, such a treatment can be applied to situations in which the atomic coherence length is of the same order of or larger than the laser wavelength, which is the case for atoms cooled below the one-photon recoil energy. We introduce families of states that are closed with respect to absorption and stimulated emission, and we establish the generalized optical Bloch equations that are satisfied by the corresponding matrix elements. The existence of velocity-selective trapping states that are linear combinations of states with different internal and translational quantum numbers is demonstrated, and the mechanism of accumulation of atoms in these trapping states by fluorescence cycles is analyzed. From a numerical solution of the generalized optical Bloch equations, we study in detail how the final atomic-momentum distribution depends on the various physical parameters: interaction time, width of the initial distribution, laser detuning, laser power, and imbalance between the two counterpropagating waves. We show that the final temperature decreases when the interaction time increases, so that there is no fundamental limit to the lowest temperature that can be achieved by such a method. Finally, possible extensions of this method to two-dimensional cooling are presented.
We report the first observation of subrecoil laser cooling in three dimensions, where we use the method of velocity-selective coherent population trapping. We have cooled a cloud of trapped metastable helium atoms to 180 nK, 22 times below the single-photon recoil temperature, with an enhancement in the momentum-space density of 16. We find that the efficiency with which the velocity-selective trap is populated can be augmented by Sisyphus-type frictional forces, while the cooling process is accompanied by the diffusion of atoms to states of very high velocity.
We present a new laser-cooling scheme based on velocity-selective optical pumping of atoms into a nonabsorbing coherent superposition of states. This method has allowed us to achieve transverse cooling of metastable 4He^{4}\mathrm{He}4He atoms to a temperature of 2 \ensuremath{\mu}K, lower than both the usual Doppler cooling limit (23 \ensuremath{\mu}K) and the one-photon recoil energy (4 \ensuremath{\mu}K). The corresponding de Broglie wavelength (1.4 \ensuremath{\mu}m) is larger than the atomic-transition optical wavelength.