Radiation force in the magneto-optical trap

Steane, Andrew M.; Chowdhury, Mihir; Foot, C. J.

doi:10.1364/josab.9.002142

Cited by 175 publications

(146 citation statements)

References 29 publications

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“…Interestingly, comparing the two loss mechanisms we find σ 3 τ 3 /σ 6 τ 6 ≈ 0.1, which shows that the resonance mechanism, dominating the background losses in the VC-MOT [23,38], is of minor importance in the present case. Since the output flux scales like (v c /α) 4 an obvious way to increase the output of MOT sources is to increase the capture velocity.…”

Section: B Loss Mechanismsmentioning

confidence: 55%

“…As the relative velocities are large and the typical collision time is much shorter than the lifetime of the atoms in the excited state we may use again the classical scattering model discussed above. In the present case the critical distance of closest approach corresponds to momentum transfer just exceeding the escape value from the 2D MOT, mv mv c [38]. Neglecting the direction of the transition dipole the resonant-dipole force can be approximated by F (r) = 3C 3 /r 4 , where the C 3 coefficient is defined as [40,41] …”

Section: B Loss Mechanismsmentioning

confidence: 93%

“…[38] and consider a slow atom moving at the capture velocity v c along the symmetry-axis from the oven towards the capture region. Fast atoms flying-by with the thermal velocityv will give rise to momentum transfer as a result of Van der Waals interaction.…”

Section: B Loss Mechanismsmentioning

confidence: 99%

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High-flux two-dimensional magneto-optical-trap source for cold lithium atoms

et al. 2009

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We demonstrate a novel 2D MOT beam source for cold 6 Li atoms. The source is side-loaded from an oven operated at temperatures in the range 600 T 700 K. The performance is analyzed by loading the atoms into a 3D MOT located 220 mm downstream from the source. The maximum recapture rate of ∼ 10 9 s −1 is obtained for T ≈ 700 K and results in a total of up to 10 10 trapped atoms. The recaptured fraction is estimated to be 30 ± 10% and limited by beam divergence. The most-probable velocity in the beam (αz) is varied from 18 to 70 m/s by increasing the intensity of a push beam. The source is quite monochromatic with a full-width at half maximum velocity spread of 11 m/s at αz = 36 m/s, demonstrating that side-loading completely eliminates beam contamination by hot vapor from the oven. We identify depletion of the low-velocity tail of the oven flux as the limiting loss mechanism. Our approach is suitable for other atomic species.

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Section: B Loss Mechanismsmentioning

confidence: 55%

Section: B Loss Mechanismsmentioning

confidence: 93%

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High-flux two-dimensional magneto-optical-trap source for cold lithium atoms

et al. 2009

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“…2) is given by τ −1 3 . Background collisions contribute with a rate of γp [16] with p being the pressure in the vacuum chamber and γ being a constant depending on the atomic and molecular species present. The parameter ML summarizes possible MOT losses.…”

mentioning

confidence: 99%

“…In all practi- cal implementations the trap depth will remain finite due to the finite size of the laser beams. Thus, for a given beam geometry, a variation in B ′ should allow to investigate the MOT stability and to quantify the MOT losses ML which include diffusive motion out of the trapping volume [19] leading to an exponentially decreasing loss rate with increasing trap depth and non-ionizing background gas collisions [16] already being accounted for by the p → 0 extrapolation. The influence of the magnetic field gradient on the measured decay rate α is shown in Fig.…”

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confidence: 99%

Precision measurement of the metastable3P2lifetime of neon

et al. 2003

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The lifetime of the metastable 3 P2 state of neon has been determined to 14.70(13) s (decay rate 0.06801(62) s −1 ) by measuring the decay in fluorescence of an ensemble of 20 Ne atoms trapped in a magneto-optical trap (MOT). Due to low background gas pressure (p < 5 × 10 −11 mbar) and low relative excitation to the 3 D3 state (0.5 % excitation probability) operation only small corrections have to be included in the lifetime extrapolation. Together with a careful analysis of residual loss mechanisms in the MOT a lifetime determination to high precision is achieved.PACS numbers: 32.70. Cs, 32.70.Fw, 32.80.Pj In contrast to its importance for various active fields of research covering such a wide range as atomic physics, quantum optics, and nuclear physics, there still has been no measurement of the natural lifetime of the metastable 3 P 2 state [1] of neon with sufficient precision. A selection of research activities profiting from an improved measurement include the quest for Bose-Einstein condensation (BEC) of metastable neon, advanced atomic structure calculations, the investigation of ultracold collisions, and even precision tests of the electroweak theory being currently persued by investigating the nuclear decay of an optically trapped sample of 19 Ne in the 3 P 2 state [2].Ongoing research directed towards BEC of metastable neon atoms in the 3 P 2 state [3, 4] clearly will benefit from an accurate knowledge of the state's lifetime. This includes the optimization of the production process as well as the study of collision processes such as Penningionization [5] and elastic s-wave scattering. Exciting new physics complementing the work on metastable helium [6,7] can be expected for a 3 P 2 neon condensate. We would like to point out the study of higher-order correlations [8] and the intriguing possibility of a modification of the 3 P 2 decay rate due to the high phase-space density or the phase coherence in a BEC [9].Significant advance in atomic structure calculations has already been and will be further triggered [10] by the work presented here. To date only a preliminary experimental value of 22 s for the 3 P 2 lifetime of neon exists [11] with no detailed investigations having been performed [12]. A precise determination of the lifetime will put a more stringent test on theory. For most rare-gas atoms, the 3 P 2 lifetime depends sensitively on electron correlations and relativistic corrections. The latter have only a minor effect for the case of neon, making neon specifically interesting for a critcal test of electron correlations. In addition, our measurement will close the chain of 3 P 2 lifetime measurements for rare-gas atoms beyond helium performed in recent years for Ar ( input for a detailed systematic investigation of the Zdependence of metastable lifetimes. An accurate experimental determination of the 3 P 2 lifetimes of rare-gas atoms other than helium has only been achievable by the ability to prepare cold atom samples in a MOT [11,13,14,15]. For a precision lifetime measurement, the coupli...

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