Intensity dependence for trap loss rate in a magneto-optical trap of strontium

Caires, Anderson R. L.; Telles, G. D.; Mancini, M.; Marcassa, Luís Gustavo; Bagnato, Vanderlei Salvador; Wilkowski, David; Kaiser, Robin

doi:10.1590/s0103-97332004000700031

Cited by 9 publications

(8 citation statements)

References 13 publications

(20 reference statements)

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“…We believe it could be explained by unwanted escape channels in the MOT or incomplete repumping of the atoms from the metastable states. We shall exclude losses due to light assisted collisions since the two-body collisional loss coefficient reported in the literature is β 2 × 10 −10 cm 3 /s [40,41]. With a peak spatial density of n 3 × 10 9 cm −3 , this leads to a small light assisted collision loss rate, estimated to be βn 0.6 s −1 .…”

Section: Blue Magneto-optical Trapmentioning

confidence: 99%

A high flux source of cold strontium atoms

et al. 2015

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We describe an experimental apparatus capable of achieving a high loading rate of strontium atoms in a magneto-optical trap operating in a high vacuum environment. A key innovation of this setup is a two dimensional magneto-optical trap deflector located after a Zeeman slower. We find a loading rate of 6 × 10 9 s −1 whereas the lifetime of the magnetically trapped atoms in the 3 P2 state is 54 s.

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Section: Blue Magneto-optical Trapmentioning

confidence: 99%

A high flux source of cold strontium atoms

et al. 2015

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“…The 022708-3 phase shift is found by matching this numerical solution in the asymptotic region to the asymptotic form [Eq. (9)] and by using −C l B l = tan δ l . The resultant values for partial wave phase shifts δ l depend on the incident wave vector magnitude k = μ| v r |/h.…”

Section: Theorymentioning

confidence: 99%

“…A well-studied example of this is the large intensity-dependent variation displayed by the two-body intratrap loss-rate coefficient for atoms trapped in a magnetooptical trap (MOT). This variation results from an interplay of trap depth and the energy imparted to trapped atoms due to hyperfine or fine structure changing collisions, as well as radiative escape [1][2][3][4][5][6][7][8][9][10][11][12]. More recently, inelastic and elastic collision rates in dipole traps have been of interest, particularly for metastable species [13,14].…”

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confidence: 99%

Trap-depth determination from residual gas collisions

et al. 2011

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We present a method for determining the depth of an atomic or molecular trap of any type. This method relies on a measurement of the trap loss rate induced by collisions with background gas particles. Given a fixed gas composition, the loss rate uniquely determines the trap depth. Because of the "soft" long-range nature of the van der Waals interaction, these collisions transfer kinetic energy to trapped particles across a broad range of energy scales, from room temperature to the microkelvin energy scale. The resulting loss rate therefore exhibits a significant variation over an enormous range of trap depths, making this technique a powerful diagnostic with a large dynamic range. We present trap depth measurements of a Rb magneto-optical trap using this method and a different technique that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state. The main advantage of the method presented here is its large dynamic range and applicability to traps of any type requiring only knowledge of the background gas density and the interaction potential between the trapped and background gas particles.The particle loss rate from a trap is one of the primary observables for probing the collisional physics of trapped gases. Measurements of trap loss are routinely made in a variety of experiments to deduce elastic and inelastic collision cross sections for intratrap collisions and for collisions between trapped species and externally introduced particles. Trap depth often plays an important role in the interpretation of these measurements. A well-studied example of this is the large intensity-dependent variation displayed by the two-body intratrap loss-rate coefficient for atoms trapped in a magnetooptical trap (MOT). This variation results from an interplay of trap depth and the energy imparted to trapped atoms due to hyperfine or fine structure changing collisions, as well as radiative escape [1][2][3][4][5][6][7][8][9][10][11][12]. More recently, inelastic and elastic collision rates in dipole traps have been of interest, particularly for metastable species [13,14]. The fraction of elastic collisions resulting in an evaporated atom depends on trap depth, which is a key parameter for evaporative cooling [13,15,16]. The lifetime dependence of a state-insenstive dipole trap on trap depth for cesium atoms has also recently been investigated [17]. Of course the most fundamental role of trap depth is that it be large enough to provide sufficient confinement, which has been an issue for experiments with buffer-gas-cooled atoms or molecules [18,19].In recent years there has been interest in making precision determinations of collision cross-sections from measurements of particle loss rates due to externally introduced particles. These measurements involve collisions of trapped neutral particles with neutral atoms and molecules [20][21][22][23][24], electron beams [25][26][27], and trapped ions [28][29][30]. Photoionization cross sections have also been investigated though mea...

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“…(14) and (15), we can define a parameter, M i , that is proportional to the loading rate for a MOT with specific laser detuning and intensity (R i ) times the scattering rate of the MOT at a standard detuning and intensity:…”

Section: Methodsmentioning

confidence: 99%

“…Both two-dimensional and three-dimensional MOTs are used extensively for the production of laser cooled ensembles of atoms. Since their invention, these devices have been studied in detail [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The use of MOTs has enabled the careful investigation into the mechanisms of laser cooling and trapping [1][2][3][4][5]10,18], intratrap cold collisions and loss from a MOT [1,9,11,14,15,17,19], and the determination of collisional cross sections and scattering from atoms in a MOT [6,7,[20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Magneto-optical trap loading rate dependence on trap depth and vapor density

et al. 2012

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We study the dependence of the particle loading rate of a rubidium vapor cell magneto-optic trap (MOT). Using a trap depth determination of the MOT that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state, we experimentally determine the MOT escape velocity and show that the loading rate scales with escape velocity to the fourth power, or, equivalently, with the square of the trap depth. We also demonstrate that the loading rate is directly proportional to the background rubidium density. We thus experimentally confirm the loading rate model used in the literature since the invention of the MOT. In addition to confirming this long-standing conjecture, we show that the loading rate dependence can be used to reliably infer the trap depth and to tune the relative depth of a MOT (i.e., capture and escape velocities) when the background density is held fixed. The measurements have allowed an experimental determination of the relationship between capture and escape velocities in our MOTs of v c 1.290.12v e .

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Intensity dependence for trap loss rate in a magneto-optical trap of strontium

Cited by 9 publications

References 13 publications

A high flux source of cold strontium atoms

A high flux source of cold strontium atoms

Trap-depth determination from residual gas collisions

Magneto-optical trap loading rate dependence on trap depth and vapor density

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