Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

International Conference on Spectral Line Shapes (ICSLS)

Theory of optical shielding in cold atom beams

Vladimir Yurovsky, A. Ben‐Reuven

Published Jan 1, 1999• 0 citations
Publisher

Abstract

Experiments were conducted recently (by Weiner and co-workers) on the optical shielding (suppression) of atomic collisions in cold-atom beams, and its variation with the angle between the polarization direction of the shielding light and the direction of approach of the beam. This case is shown here to be a typical example of an optical collision in which quantum interference may persevere between two incident collision partial waves leading to the same output state. This effect depends on the relative collisional phaseshift of the two interfering channels, as well as on the angle of approach, and will vanish when averaging over the latter (as with collisions in the bulk). The extent of variation of this interference effect with the relative phaseshift is quite broad, and may lead, under favorable conditions, to almost complete shielding at a finite value of the shielding-laser power. The latter observation leaves open the possibility of exerting coherent control over the interference effect in order to optimize the shielding.

DOI
10.1063/1.58320

Related papers

Channel Interference in Optical Collisions of Cold Atom Beams

Vladimir Yurovsky, A. Ben‐Reuven

Experiments were conducted recently (by Weiner and co-workers) on the optical shielding (suppression) of atomic collisions in cold-atom beams, and its variation with the angle between the polarization direction of the shielding light and the direction of approach of the beam. This case is shown here to be a typical example of an optical collision in which quantum interference may persevere between two incident collision partial waves leading to the same output state. This effect depends on the relative collisional phase shift of the two interfering channels, as well as on the angle of approach, and will vanish when averaging over the latter (as with collisions in the bulk). The extent of variation of this interference effect with the relative phase shift is quite broad, and may lead, under favorable conditions, to almost complete shielding at a finite value of the shielding-laser power. The latter observation leaves open the possibility of exerting coherent control over the interference effect in order to optimize the shielding.

The Journal of Physical Chemistry A•Nov 1, 1998•16 citations

Incomplete optical shielding in cold sodium atom traps

Vladimir Yurovsky, A. Ben‐Reuven

A simple two-channel model, based on the semiclassical Landau-Zener (LZ) approximation, with averaging over angle-dependent exponents, is proposed as a fast means for accounting for the incomplete optical shielding of collisions, as observed in recent experiments conducted by Weiner and co-workers on ultracold sodium-atom traps, and its dependence on the laser polarization. The model yields a reasonably good agreement with the recent quantum close-coupling calculations of Julienne and co-workers. The remaining discrepancy between both theories and the data is qualitatively attributed to a partial overlap of the collision ranges at which loss processes and optical shielding occur.

AIP conference proceedings•Jan 1, 1997•0 citations

Incomplete optical shielding in cold atom traps: three-dimensional Landau-Zener theory

Vladimir Yurovsky, A. Ben‐Reuven

Ultracold atom collisions in the presence of a linearly polarized blueshifted laser field are studied theoretically. An analytical solution is presented within the framework of the Landau-Zener approximation. The effect of incomplete shielding is mostly accounted for by incorporating the three-dimensional character of the collisions, using a partial-wave analysis with space degeneracy. A model of two electronic states, including effects of indistinguishability of the colliding atoms, is used. The model associates the incomplete shielding with a process involving two crossing points. The theory is applied to the case of metastable xenon traps, obtaining a fair agreement with the experimental data.

Physical Review A•May 1, 1997•13 citations

Theories for cold atomic collisions in light fields

Kalle‐Antti Suominen

I describe the current theories for cold collisions between laser-cooled and trapped neutral atoms in light fields. The emphasis is on the dynamical nature of the problem, i.e. on the collisional loss of atoms from the trap or collisional heating of the atomic cloud. The recent work on optical shielding of collisions is also reviewed.

Journal of Physics B Atomic Molecular and Optical Physics•Dec 28, 1996•69 citations

Collisions of Ultracold Atoms in Optical Fields

Daniel J. Heinzen, D. J. Wineland, Carl Wieman +1 more

Two recent developments in ultracold atomic collision physics are discussed. The first is the “optical shielding” of ultracold atomic collisions by optical radiation that is tuned to the blue of an atomic resonance. This radiation couples a pair of colliding atoms to repulsive excited states and prevents their close approach. This effect may substantially suppress inelastic collision rates, and is an interesting example of the control of a cold collision process by a weak perturbing field. The second topic is ultracold atom photoassociation spectroscopy. In this work, high resolution free‐bound absorption spectra are obtained which provide detailed information on the long‐range states of the two interacting atoms. The physics of these states has an appealing simplicity, and in addition is of importance for a complete understanding of the effects of atomic interactions in cold atom experiments. The photoassociation spectra also provide a unique probe of cold collisions.

AIP conference proceedings•Jan 1, 1994•5 citations

Engineering long-range interactions between ultracold atoms with light

Ting Xie, Andrea Orbán, Xiaodong Xing +4 more

Abstract Ultracold temperatures in dilute quantum gases opened the way to an exquisite control of matter at the quantum level. Here we focus on the control of ultracold atomic collisions using a laser to engineer their interactions at large interatomic distances. We show that the entrance channel of two colliding ultracold atoms can be coupled to a repulsive collisional channel by the laser light so that the overall interaction between the two atoms becomes repulsive: this prevents them to come close together and to undergo inelastic processes, thus protecting the atomic gases from unwanted losses. We illustrate such an optical shielding (OS) mechanism with 39 K and 133 Cs atoms colliding at ultracold temperature (<1 μK). The process is described in the framework of the dressed-state picture and we then solve the resulting stationary coupled Schrödinger equations. The role of spontaneous emission and photoinduced inelastic scattering is also investigated as possible limitations of the shielding efficiency. We predict an almost complete suppression of inelastic collisions over a broad range of Rabi frequencies and detunings from the 39 K D2 line of the OS laser, both within the [0, 200 MHz] interval. We found that the polarization of the shielding laser has a minor influence on this efficiency. This proposal could easily be formulated for other bialkali-metal pairs as their long-range interaction are all very similar to each other.

arXiv:2110.15240•Journal of Physics B Atomic Molecular and Optical Physics•Jan 13, 2022•5 citations
Experiments were conducted recently (by Weiner and co-workers) on the optical shielding (suppression) of atomic collisions in cold-atom beams, and its variation with the angle between the polarization direction of the shielding light and the direction of approach of the beam. This case is shown here to be a typical example of an optical collision in which quantum interference may persevere between two incident collision partial waves leading to the same output state. This effect depends on the relative collisional phaseshift of the two interfering channels, as well as on the angle of approach, and will vanish when averaging over the latter (as with collisions in the bulk). The extent of variation of this interference effect with the relative phaseshift is quite broad, and may lead, under favorable conditions, to almost complete shielding at a finite value of the shielding-laser power. The latter observation leaves open the possibility of exerting coherent control over the interference effect in order to optimize the shielding.
Experiments were conducted recently (by Weiner and co-workers) on the optical shielding (suppression) of atomic collisions in cold-atom beams, and its variation with the angle between the polarization direction of the shielding light and the direction of approach of the beam. This case is shown here to be a typical example of an optical collision in which quantum interference may persevere between two incident collision partial waves leading to the same output state. This effect depends on the relative collisional phase shift of the two interfering channels, as well as on the angle of approach, and will vanish when averaging over the latter (as with collisions in the bulk). The extent of variation of this interference effect with the relative phase shift is quite broad, and may lead, under favorable conditions, to almost complete shielding at a finite value of the shielding-laser power. The latter observation leaves open the possibility of exerting coherent control over the interference effect in order to optimize the shielding.
A simple two-channel model, based on the semiclassical Landau-Zener (LZ) approximation, with averaging over angle-dependent exponents, is proposed as a fast means for accounting for the incomplete optical shielding of collisions, as observed in recent experiments conducted by Weiner and co-workers on ultracold sodium-atom traps, and its dependence on the laser polarization. The model yields a reasonably good agreement with the recent quantum close-coupling calculations of Julienne and co-workers. The remaining discrepancy between both theories and the data is qualitatively attributed to a partial overlap of the collision ranges at which loss processes and optical shielding occur.
Ultracold atom collisions in the presence of a linearly polarized blueshifted laser field are studied theoretically. An analytical solution is presented within the framework of the Landau-Zener approximation. The effect of incomplete shielding is mostly accounted for by incorporating the three-dimensional character of the collisions, using a partial-wave analysis with space degeneracy. A model of two electronic states, including effects of indistinguishability of the colliding atoms, is used. The model associates the incomplete shielding with a process involving two crossing points. The theory is applied to the case of metastable xenon traps, obtaining a fair agreement with the experimental data.
Two recent developments in ultracold atomic collision physics are discussed. The first is the “optical shielding” of ultracold atomic collisions by optical radiation that is tuned to the blue of an atomic resonance. This radiation couples a pair of colliding atoms to repulsive excited states and prevents their close approach. This effect may substantially suppress inelastic collision rates, and is an interesting example of the control of a cold collision process by a weak perturbing field. The second topic is ultracold atom photoassociation spectroscopy. In this work, high resolution free‐bound absorption spectra are obtained which provide detailed information on the long‐range states of the two interacting atoms. The physics of these states has an appealing simplicity, and in addition is of importance for a complete understanding of the effects of atomic interactions in cold atom experiments. The photoassociation spectra also provide a unique probe of cold collisions.
Abstract Ultracold temperatures in dilute quantum gases opened the way to an exquisite control of matter at the quantum level. Here we focus on the control of ultracold atomic collisions using a laser to engineer their interactions at large interatomic distances. We show that the entrance channel of two colliding ultracold atoms can be coupled to a repulsive collisional channel by the laser light so that the overall interaction between the two atoms becomes repulsive: this prevents them to come close together and to undergo inelastic processes, thus protecting the atomic gases from unwanted losses. We illustrate such an optical shielding (OS) mechanism with 39 K and 133 Cs atoms colliding at ultracold temperature (<1 μK). The process is described in the framework of the dressed-state picture and we then solve the resulting stationary coupled Schrödinger equations. The role of spontaneous emission and photoinduced inelastic scattering is also investigated as possible limitations of the shielding efficiency. We predict an almost complete suppression of inelastic collisions over a broad range of Rabi frequencies and detunings from the 39 K D2 line of the OS laser, both within the [0, 200 MHz] interval. We found that the polarization of the shielding laser has a minor influence on this efficiency. This proposal could easily be formulated for other bialkali-metal pairs as their long-range interaction are all very similar to each other.