Scaling laws for large magneto-optical traps

Gattobigio, G. L.; Pohl, Thomas; Labeyrie, G.; Kaiser, Robin

doi:10.1088/0031-8949/81/02/025301

Cited by 29 publications

(35 citation statements)

References 23 publications

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“…Possible explanations for this behavior included the effect of the magnetic field gradient and high-order multiple scattering of light inside the cloud. A more involved (numerical) model [7] surprisingly led to the same L ∝ N 1/3 scaling, although the calculated density profiles were no longer homogeneous but displayed a truncated Gaussian shape [7]. This model takes into account the nonlinear form of both trapping and shadow forces and the spatial dependence of the interaction force.…”

Section: Vlmot Size Scalingmentioning

confidence: 80%

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Scaling behavior of a very large magneto-optical trap

Camara¹,

Kaiser²,

Labeyrie³

2014

Phys. Rev. A

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We investigate the scaling behavior of a very large magneto-optical trap (VLMOT) containing up to 1.4 × 10 11 Rb 87 atoms. By varying the diameter of the trapping beams, we are able to change the number of trapped atoms by more than 5 orders of magnitude. We then study the scaling laws of the loading and size of the VLMOT, and analyze the shape of the density profile in this regime where the Coulomb-like, light-mediated repulsive interaction between atoms is expected to play an important role.

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Section: Vlmot Size Scalingmentioning

confidence: 80%

“…In ref. [7], we have shown that using different techniques to vary the number of atoms (i.e. tuning the intensity or the diameter of a repumping beam) could yield different scaling laws for the MOT size.…”

Section: Vlmot Size Scalingmentioning

confidence: 99%

Scaling behavior of a very large magneto-optical trap

Camara¹,

Kaiser²,

Labeyrie³

2014

Phys. Rev. A

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“…[19]. For typical 85 Rb MOT, δ = −Γ 0 /2 and ∇B = 10 Gcm −1 , we get a density n 0 = 3 × 10 9 cm −3 .…”

mentioning

confidence: 72%

Polytropic equilibrium and normal modes in cold atomic traps

Terças¹,

Mendonça

2013

Phys. Rev. A

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The compressibility limit of a cold gas confined in a magneto-optical trap due to multiple scattering of light is a long-standing problem. This scattering mechanism induces long-range interactions in the system, which is responsible for the occurrence of plasma-like phenomena. In the present paper, we investigate the importance of the long-range character of the mediated atom-atom interaction in the equilibrium and dynamical features of a magneto-optical trap. Making use of a hydrodynamical formulation, we derive a generalized Lane-Emden equation modeling the polytropic equilibirum of a magneto-optical trap, allowing us to describe the cross-over between the two limiting cases: temperature dominated and multiple-scattering dominated traps. The normal collective modes of the system are also computed.Introduction. Since the first realizations of cold atomic gases [1], both theoretical and experimental investigations reveal that magneto-optical traps (MOT) pave a stage for very exciting and complex physical phenomena [2]. The interest in studying the basic properties of MOTs have, however, considerably decreased after the production of Bose-Einstein condensates [3,4], as they started being used mainly as a riding horse to achieve quantum degeneracy. However, the study of the dynamical properties of MOTs have received much attention recently, which revives the investigation of the basic properties of laser cooled gases. Examples of such a growing interest can be found in the work realized by Kim et al. [5], where a parametric instability is excited by an intensity modulated laser beam, and in the works of di Steffano and co-workers [6][7][8], where the feedback of retroreflected laser beams can induce stochastic or deterministic chaos for a large optical thickness of the MOT.A route for the most intriguing complex behavior in magneto-optical traps relies exactly on the multiple scattering of light, a mechanism which have been described since the early stages of MOTs as the principal limitation for the compressibility of the cloud [9,10]. Under these circumstances, the atoms experience a mediated long-range interaction potential similar to a Coulomb potential (∼ 1/r) [11] and the system can therefore be regarded as a one-component trapped plasma. In a series of previous works, we have put in evidence the important consequences of such plasma description of a cold atomic traps [12], whereas the formal analogy and the application of plasma physics techniques reveal to be important in the description of driven mechanical instabilities [14] or even more exciting instability phenomena, like photon bubbles [15], phonon lasing [16] or even the appearance of a roton minimum in the classical regime [17].In this work, we investigate the hydrodynamic equilibrium and normal modes of cold atomic traps. For that

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“…The atomic spatial density at the center of the cloud is given by ρ 0 = N/( √ 2πR) 3 . Using the notation r = (x, y, z) = (r ⊥ , z), the optical thickness at the center of the cloud (r ⊥ = 0) is defined as…”

Section: Contributions To the Radiation Pressure Forcementioning

confidence: 99%

Collective effects in the radiation pressure force

et al. 2016

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We discuss the role of diffuse, Mie and cooperative scattering on the radiation pressure force acting on the center of mass of a cloud of cold atoms. Even though a mean-field Ansatz (the 'timed Dicke state'), previously derived from a cooperative scattering approach, has been shown to agree satisfactorily with experiments, diffuse scattering also describes very well most features of the radiation pressure force on large atomic clouds. We compare in detail an incoherent, random walk model for photons and a diffraction approach to the more complete description based on coherently coupled dipoles. We show that a cooperative scattering approach, although it provides a quite complete description of the scattering process, is not necessary to explain the previous experiments on the radiation pressure force.

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Scaling laws for large magneto-optical traps

Cited by 29 publications

References 23 publications

Scaling behavior of a very large magneto-optical trap

Scaling behavior of a very large magneto-optical trap

Polytropic equilibrium and normal modes in cold atomic traps

Collective effects in the radiation pressure force

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