Optical shielding of cold collisions in blue-detuned near-resonant optical lattices

Piilo, Jyrki; Suominen, Kalle-Antti

doi:10.1103/physreva.66.013401

Cited by 6 publications

(20 citation statements)

References 48 publications

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“…Despite of this, we think that our study is useful because of two reasons: a) we can give results for collision rates in the density region where the rescattering effects do not appear, b) because for very high densities (where rescattering effects should be accounted in principle) one could still use the method presented here to study the aspects of the binary collision effects on the lattice dynamics of the atomic cloud. This in itself is very complex problem, and also worth studying 17,18,19 . From a Monte Carlo method point of view there is an interesting feature present here.…”

Section: Discussionmentioning

confidence: 99%

“…24-26 for applications of the method to the cold collision problems) to calculate the collision rates. We have also applied the method recently to study heating in red-detuned 17,18 and optical shielding in bluedetuned lattices 19 . The schematic view of the optical potentials for the two ground state Zeeman sublevels.…”

Section: Monte Carlo Wave Function Methodsmentioning

confidence: 99%

“…The accumulation of the atomic population beyond z a gives information about the atomic quantum transport in a lattice and can be monitored by MCWF simulations for one atom. Thus, our method avoids the requirement of large computational resources of the two-atom MCWF collision simulations 17,18,19 . To illustrate the usefulness of the method we calculate the collision rates for various modulation depths and occupation densities of one dimensional optical lattices.…”

Section: Introductionmentioning

confidence: 99%

“…So far, to the best of our knowledge, there has been only a few experimental cold collision studies in optical lattices 10,11 . Theoretical studies of the interactions between atoms in optical lattices include the meanfield type approaches 12,13,14,15,16 , and Monte Carlo wave function (MCWF) simulations of binary collisions in red detuned 17,18 and blue detuned lattices 19 . However, the mean-field approaches neglect the dynamical nature of the collisions, and the MCWF simulations for two atoms colliding in optical lattice require extremely large computer resources 18 .…”

Section: Introductionmentioning

confidence: 99%

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Collision rates in near-resonant optical lattices

Piilo

2003

J. Opt. Soc. Am. B

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We present a simple method to calculate the binary collision rate between atoms in near-resonant optical lattices. The method is based on the Monte Carlo wave function simulations and the collision rate is obtained by monitoring the quantum flux beyond the average distance between the atoms. To illustrate the usefulness of the method, we calculate the collision rates for a wide range of occupation densities and various modulation depths of the lattice. The method presented here combined with the semiclassical calculations accounting for intra-well collisions can simplify the study of the effects of binary collisions on the dynamics of atomic clouds trapped in near-resonant optical lattices.

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Section: Discussionmentioning

confidence: 99%

Section: Monte Carlo Wave Function Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Collision rates in near-resonant optical lattices

Piilo

2003

J. Opt. Soc. Am. B

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“…Typically our ensembles have 64 or 128 members, which is quite sufficient for calculating the bulk properties such as average kinetic energy [14,26]. In cold collision studies this method has been applied previously to two-state models [14,26], to collisions in optical lattices [28,29], and an initial step towards including the partial waves to cold collision problems was presented in Ref. [22].…”

Section: Monte Carlo Simulationsmentioning

confidence: 99%

Cold collisions in strong laser fields: partial wave analysis of magnesium collisions

2006

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Abstract. We have developed Monte Carlo wave function simulation schemes to study cold collisions between magnesium atoms in a strong red-detuned laser field. In order to address the strong-field problem, we extend the Monte Carlo wave function framework to include the partial wave structure of the threedimensional system. The average heating rate due to radiative collisions is calculated with two different simulation schemes which are described in detail. We show that the results of the two methods agree and give estimates for the radiative collision heating rate for 24 Mg atoms in a magneto-optical trap based on the 1 S0-1 P1 atomic laser cooling transition.

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Cold collisions in dissipative optical lattices

Piilo¹,

Suominen²

2005

J. Opt. B: Quantum Semiclass. Opt.

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The invention of laser cooling methods for neutral atoms allows optical and magnetic trapping of cold atomic clouds in the temperature regime below 1mK. In the past, light-assisted cold collisions between laser cooled atoms have been widely studied in magneto-optical atom traps (MOTs). We describe here theoretical studies of dynamical interactions, specifically cold collisions, between atoms trapped in near-resonant, dissipative optical lattices. The extension of collision studies to the regime of optical lattices introduces several complicating factors. For the lattice studies, one has to account for the internal substates of atoms, position dependent matter-light coupling, and position dependent couplings between the atoms, in addition to the spontaneous decay of electronically excited atomic states. The developed one-dimensional quantum-mechanical model combines atomic cooling and collision dynamics in a single framework. The model is based on Monte Carlo wave-function simulations and is applied when the lattice-creating lasers have frequencies both below (reddetuned lattice) and above (blue-detuned lattice) the atomic resonance frequency. It turns out, that the radiative heating mechanism affects the dynamics of atomic cloud in a red-detuned lattice in a way that is not directly expected from the MOT studies. The optical lattice and position dependent light-matter coupling introduces selectivity of collision partners. The atoms, which are most mobile and energetic, are strongly favored to participate in collisions, and are more often ejected from the lattice, than the slow ones in the laser parameter region selected for study. Consequently, the atoms remaining in the lattice have a smaller average kinetic energy per atom than in the case of non-interacting atoms. For bluedetuned lattices, we study how optical shielding emerges as a natural part of the lattice and look for ways to optimize the effect. We find that the cooling and shielding dynamics do not mix and it is possible to achieve efficient shielding with a very simple arrangement. The simulations are computationally very demanding and would obviously benefit from the simplification schemes. We present some steps to this direction by showing how it is possible to calculate collision rates in near-resonant lattices in a fairly simple way. The method can then be used to combine quantum-mechanical and semiclassical models for cold collision studies in optical lattices.

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Optical shielding of cold collisions in blue-detuned near-resonant optical lattices

Cited by 6 publications

References 48 publications

Collision rates in near-resonant optical lattices

Collision rates in near-resonant optical lattices

Cold collisions in strong laser fields: partial wave analysis of magnesium collisions

Cold collisions in dissipative optical lattices

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