Collisional loss rate of sodium atoms in a magneto-optical trap operating on the D1 line

Marcassa, Luís Gustavo; Helmerson, Kristian; Tuboy, A M; Milori, Débora Marcondes Bastos Pereira; Muniz, Sérgio Ricardo; Flemming, J.; Zílio, Sérgio Carlos; Bagnato, Vanderlei Salvador

doi:10.1088/0953-4075/29/14/017

Cited by 13 publications

(9 citation statements)

References 14 publications

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“…As expected, the capture velocity increases with increasing intensity. Fitting these data to the model v c = aI b t yields b = 0.73 (2). Figure 2(c) shows how v c depends on the detuning, ∆ 11 , when I t = 260 mW/cm 2 and B = 39 G/cm.…”

Section: Blue-detuned Motsmentioning

confidence: 96%

“…Normally, atomic MOTs operate on type-I transitions, where the hyperfine angular momentum of the excited state (F ) exceeds that of the ground state (F ), F = F + 1. Examples also exist of type-II atomic MOTs [2][3][4][5], which have F ≤ F , but these have the unfavourable properties of high temperature and low density, and so have not received much attention. Recently, a number of groups have demonstrated magneto-optical trapping of diatomic molecules [6][7][8], which are cooled using type-II transitions [9], and this has generated a renewed interest in understanding the properties of type-II MOTs [10,11].…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of unconventional Rb magneto-optical traps

2018

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We study several new magneto-optical trapping configurations in 87 Rb. These unconventional MOTs all use type-II transitions, where the angular momentum of the ground state is greater than or equal to that of the excited state, and they may use either red-detuned or blue-detuned light. We describe the conditions under which each new MOT forms. The various MOTs exhibit an enormous range of lifetimes, temperatures and density distributions. At the detunings where they are maximized, the lifetimes of the various MOTs vary from 0.1 to 15 s. One MOT forms large ring-like structures with no density at the centre. The temperature in the red-detuned MOTs can be three orders of magnitude higher than in the blue-detuned MOTs. We present measurements of the capture velocity of a blue-detuned MOT, and we study how the loss rate due to ultracold collisions depends on laser intensity and detuning. arXiv:1807.07655v1 [physics.atom-ph]

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Section: Blue-detuned Motsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Characteristics of unconventional Rb magneto-optical traps

2018

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“…Since the excited electron in a Rydberg atom is very loosely bound to its ionic core, Rydberg atoms exhibit very high polarizability. As a result, the interactions between Rydberg atoms can be particularly strong [1]. Rydberg atom interactions can be resources or liabilities depending on how the Rydberg atoms are employed.…”

Section: Introductionmentioning

confidence: 99%

“…Phenomena such as the formation of novel types of molecules [8], collisions between ultracold Rydberg atoms, including the effect of electric fields [9,10], and dipole-dipole and van der Waals interactions [1,11] have been investigated. The Rydberg atom blockade effect [12], whose basis lies in the strength of the Rydberg atom interactions, has attracted widespread attention.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic interactions in electric field polarized ultracold Rydberg gases

Jahangiri

Shaffer

Gonçalves

et al. 2019

J. Phys. B: At. Mol. Opt. Phys.

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We calculate pair potential curves for interacting Rydberg atoms in a constant electric field and use them to determine the effective C 3 dipole-dipole and C 6 van der Waals coefficients. We compare the C 3 and C 6 with experiments where the angle of a polarizing electric field is varied with respect to the axis of a quasi-1-dimensional trap at ultracold temperatures. The dipoles produced via polarization of the atoms have an angular dependent dipole-dipole interaction. We focus on the interaction potential of two rubidium Rydberg atoms in 50S 1/2 states in the blockade regime.For internuclear distances close to the blockade radius, R bl ≈ 4 − 6 µm, molecular calculations are in much better agreement with experimental results than those based on the properties of single atoms and independent calculations of C 3 and C 6 which were used to analyze the original experiment. We find that the calculated C 6 coefficient is within 8% of the experimental value while the C 3 coefficient is within 20% of the experimental value.

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“…Thus, the only remaining possibility is to use polychromatic laser fields with different polarization. This approach is closely related to studies of magnetooptical trap (mainly on Na or Rb [32][33][34][35][36][37][38]) with cooling and repumping lasers either tuned on (i) pure D 2 (standard type I MOT using F → F + 1, or more interestingly for our purpose, type II MOT using F → F −1 or F → F transitions [39]), (ii) pure D 1 [40,41] or (iii) D 1 and D 2 (type III MOT [42,43]) [47]. However, these studies only consider the case where the two laser fields drive different levels.…”

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confidence: 99%

Bichromatic magneto-optical trapping forJ→J,J−1configurations

et al. 2016

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A magneto-optical trap (MOT) of atoms or molecules is studied when two lasers of different detunings and polarization are used. Especially for J → J, J − 1 transitions, a scheme using more than one frequency per transition and different polarization is required to create a significant force. Calculations have been performed with the simplest forms of the J → J − 1 case (i.e. J ′′ = 1 → J ′ = 0) and J → J case (i.e. J ′′ = 1/2 → J ′ = 1/2). A one dimensional (1D) model is presented and a complete 3D simulation using rate equations confirm the results. Even in the absence of Zeeman effect in the excited state, where no force is expected in the single laser field configuration, we show that efficient cooling and trapping forces are restored in our configuration. We study this mechanism for the C − 2 molecular anion as a typical example of the interplay between the two simple transitions J → J, J − 1. Laser cooling and magneto-optical trapping of atoms typically involves J → J + 1 closed transitions driven by counter-propagating circularly polarized laser fields (J is the total angular momentum). On the contrary laser forces on molecule, a more recent subject despite the pioneer experiments [1,2], typically involve N ′′ = 1 → N ′ = 0 transitions (N is the rotational quantum number) between X 2 Σ(v ′′ = 0) and A 2 Π 1/2 (v ′ = 0) vibronic levels [3][4][5]. Including the electron spin leads to J ′′ = 1/2, 3/2 → J ′ = 1/2 transitions. Theoretical study of the correct choice of circular polarization for magnetooptical trapping depending on the angular momenta, J ′′ and J ′ , and on the g-factors, g ′′ and g ′ (respectively of the lower and upper states) has been performed in Ref [6]. It has been found heuristically that the trapping force is weak whenever g ′ is small compared to g ′′ . This is a serious limitation because in pure Hund's case (a) or (b), A 2 Π 1/2 does not present any Zeeman effect [7], so g ′ = 0 prevents any force. However experiments, such as that on SrF [8], were possible because of rotational and spin-orbit Π − Σ mixing allowing a small non zero value for g ′ (∼ 0.1 [6]). In addition to this weak force, J ′′ = 1/2, 3/2 → J ′ = 1/2 transitions present one or two dark states [9, 10] which leads to experimental difficulties if a stronger confining force is desired. Yet stronger force can be produced by rapidly switching the magnetic field gradient and laser beam polarization on a timescale (typically in the sub-microsecond range which is not a simple experimental task) preventing the adiabatic following of the atomic states as done in reference [3] .In this letter we suggest that efficient magneto-optical forces can be restored in all J ′′ → J ′ cases, even for g ′ = 0, in a very simple way, by simply adding one laser field of opposite polarization with a different detuning. We treat the simplest J → J − 1 case (that * Corresponding author: anne.cournol@u-psud.fr is J ′′ = 1 → J ′ = 0) and J → J case (that is J ′′ = 1/2 → J ′ = 1/2). An analytical one dimensional (1D) model is presented and help get t...

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Collisional loss rate of sodium atoms in a magneto-optical trap operating on the D1 line

Cited by 13 publications

References 14 publications

Characteristics of unconventional Rb magneto-optical traps

Characteristics of unconventional Rb magneto-optical traps

Anisotropic interactions in electric field polarized ultracold Rydberg gases

Bichromatic magneto-optical trapping forJ→J,J−1configurations

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