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

Journal of Physics B Atomic Molecular and Optical Physics

Strong collision model for light-induced drift of multi-level atoms

Alan D. Streater, J. P. Woerdman

Published Feb 28, 1989• 22 citations
Publisher

Abstract

The authors calculate the light-induced drift velocity of multi-level atoms in the strong collision approximation. The solution is presented in a general form which can be easily applied to various systems. Specific calculations of drift velocities are presented for the system Rb:Ar for the cases of single- and multi-frequency laser excitations. A calculation is also presented for the case of a white light excitation spectrum with a spectral dip, which could be caused by absorption of light by another substance in the vapour, for instance in stellar atmospheres.

DOI
10.1088/0953-4075/22/4/013

Related papers

White-light-induced drift of three-level atoms

Vasily G. Arkhipkin, D. G. Korsukov, A. K. Popov

It is shown that non-laser radiation with a broad-band spectrum can induce a drift of optically absorbing multi-level atoms through buffer gas and separate them. It is not necessary to have a mixture of absorbing species to form an asymmetry in the initially flat light spectrum with respect to the atomic resonances. The spectrum asymmetry required for a velocity-selective excitation of the atoms may be formed in the propagating light due to the difference in absorption indexes at nearby transitions of the same species. A set of kinetic equations for coupled light and particles is presented. Numerical analysis of the problem and estimations are done for several typical cases.

Journal of Physics B Atomic Molecular and Optical Physics•Feb 14, 1991•3 citations

Spectral anomalies of light-induced drift of rubidium and lithium under monochromatic excitation

Faris Gel’mukhanov, А. И. Пархоменко, Timofei Privalov +1 more

The anomalous light-induced drift (LID) of atoms caused by a velocity dependence of collision frequencies has been investigated in the frame of the theory without adjustable parameters. Our results open the possibility of experimental probing of models of interatomic potentials. The extension of the strong-collision model to the case of velocity-dependent collision rates, is the basis of our approach. The obtained model describes the anomalous LID both in the case of arbitrary mass ratio of absorbing- and buffer-gas particles and in the case of arbitrary ratio of the homogeneous and Doppler widths. In particular, we applied our model to describe the anomalous LID in alkali - noble-gas mixtures (Rb - Kr and Li - Ne systems). Qualitatively another anomaly of the LID velocity was also found in the low-pressure region. As pointed out, the optical pumping effect and the hyperfine structure of the ground electronic state, but not the velocity dependence of the collision rates, are the sources of this new anomaly.

Journal of Physics B Atomic Molecular and Optical Physics•Apr 14, 1997•14 citations

Separation of two atomic species by white-light-induced drift

A. K. Popov, Anatolii M. Shalagin, Alan D. Streater +1 more

A source of white light (i.e., with a flat spectrum) can separate the components of a gas mixture. This effect, which may have applications in stellar atmospheres, is due to light-induced drift which appears when absorption lines form in the intensity spectrum of the propagating light. We theoretically discuss the effect in its simplest form: white light shining into a gas containing two optically absorbing species and a buffer gas. Transport equations are presented, assuming two-level atoms and ignoring stimulated emission. Several limiting cases are discussed analytically. A numerical solution is also presented and used to estimate the ranges of validity of the analytical solutions.

Physical Review A•Jul 1, 1989•13 citations

Numerical study of light-induced drift of Na in noble gases

Jos E. M. Haverkort, H. G. C. Werij, J. P. Woerdman

We present a model for light-induced drift (LID) in the Na--noble-gas system which should enable direct comparison with experiment. In contrast to previous theories of LID based on a two-level description of the optical absorbers and on a simplified collision treatment, the present model is based on a realistic description of laser-driven Na atoms immersed in a buffer gas. Starting from the generalized Bloch equations, we introduce a rate-equation model for the velocity distributions in the four important Na levels. The velocity-changing and fine-structure-changing collisions are described using composite Keilson-Storer collision kernels in which all adjustable parameters have been eliminated by using available literature data. We apply the model in numerical calculations of LID as a function of all experimentally accessible parameters. It is found that the ground-state hyperfine splitting can have large effects on LID, whereas the excited-state fine-structure splitting has not. The paper establishes criteria for optimum LID effects; when using a single-frequency laser the maximum attainable drift velocity is predicted to be 13.8 m/s. Using a proper set of boundary conditions, we find a pressure dependence of LID qualitatively different from the predictions based on previous work. Finally, the influence of the collision model is investigated. We find that LID is independent of the shape of the collision kernel, indicating that a strong-collision model is always valid.

Physical Review A•Oct 1, 1988•25 citations

White-light-induced drift in a gas with one optically active species

Alan D. Streater

A new light-induced drift effect is discussed in which a white-light source separates a gas mixture containing a single optically active (absorbing) species and a buffer gas which does not interact with the light. A three-level model with one upper level and two closely spaced lower levels is used for the active atoms, and strong collisions with the more abundant surrounding buffer gas atoms are assumed. The intensity spectrum in the vapor (including the effects of hyperfine pumping), and the resulting drift velocity are calculated as a function of optical depth into the vapor.

Physical Review A•Jan 1, 1990•8 citations

Theory of high-field effects in light-induced drift

Faris Gel’mukhanov, Jos E. M. Haverkort, S. W. M. Borst +1 more

We address theoretically the effects of a large laser intensity on the phenomenon of light-induced drift. The velocity selectivity of the atom-field interaction decreases due to saturation broadening and this leads to a maximum of the drift velocity as a function of the laser intensity. Analytical expressions for the drift velocity are derived in the case of two-level atoms, assuming a strong collision model. Consequences of this high-field effect are discussed for various manifestations of light-induced drift such as propagation of a soliton in an infinitely long cell, described by the Burgers equation, and collisions of such solitons. The analogy with hydrodynamic shock waves, described by the same Burgers equation, is fruitfully explored. We also address high-field effects on the density distribution produced by light-induced drift in a finite cell. In all these manifestations of light-induced drift the cases of high field and low field show qualitatively different behaviors which are of a complementary nature.

Physical Review A•Jul 1, 1987•18 citations
The authors calculate the light-induced drift velocity of multi-level atoms in the strong collision approximation. The solution is presented in a general form which can be easily applied to various systems. Specific calculations of drift velocities are presented for the system Rb:Ar for the cases of single- and multi-frequency laser excitations. A calculation is also presented for the case of a white light excitation spectrum with a spectral dip, which could be caused by absorption of light by another substance in the vapour, for instance in stellar atmospheres.
It is shown that non-laser radiation with a broad-band spectrum can induce a drift of optically absorbing multi-level atoms through buffer gas and separate them. It is not necessary to have a mixture of absorbing species to form an asymmetry in the initially flat light spectrum with respect to the atomic resonances. The spectrum asymmetry required for a velocity-selective excitation of the atoms may be formed in the propagating light due to the difference in absorption indexes at nearby transitions of the same species. A set of kinetic equations for coupled light and particles is presented. Numerical analysis of the problem and estimations are done for several typical cases.
The anomalous light-induced drift (LID) of atoms caused by a velocity dependence of collision frequencies has been investigated in the frame of the theory without adjustable parameters. Our results open the possibility of experimental probing of models of interatomic potentials. The extension of the strong-collision model to the case of velocity-dependent collision rates, is the basis of our approach. The obtained model describes the anomalous LID both in the case of arbitrary mass ratio of absorbing- and buffer-gas particles and in the case of arbitrary ratio of the homogeneous and Doppler widths. In particular, we applied our model to describe the anomalous LID in alkali - noble-gas mixtures (Rb - Kr and Li - Ne systems). Qualitatively another anomaly of the LID velocity was also found in the low-pressure region. As pointed out, the optical pumping effect and the hyperfine structure of the ground electronic state, but not the velocity dependence of the collision rates, are the sources of this new anomaly.
A source of white light (i.e., with a flat spectrum) can separate the components of a gas mixture. This effect, which may have applications in stellar atmospheres, is due to light-induced drift which appears when absorption lines form in the intensity spectrum of the propagating light. We theoretically discuss the effect in its simplest form: white light shining into a gas containing two optically absorbing species and a buffer gas. Transport equations are presented, assuming two-level atoms and ignoring stimulated emission. Several limiting cases are discussed analytically. A numerical solution is also presented and used to estimate the ranges of validity of the analytical solutions.
We present a model for light-induced drift (LID) in the Na--noble-gas system which should enable direct comparison with experiment. In contrast to previous theories of LID based on a two-level description of the optical absorbers and on a simplified collision treatment, the present model is based on a realistic description of laser-driven Na atoms immersed in a buffer gas. Starting from the generalized Bloch equations, we introduce a rate-equation model for the velocity distributions in the four important Na levels. The velocity-changing and fine-structure-changing collisions are described using composite Keilson-Storer collision kernels in which all adjustable parameters have been eliminated by using available literature data. We apply the model in numerical calculations of LID as a function of all experimentally accessible parameters. It is found that the ground-state hyperfine splitting can have large effects on LID, whereas the excited-state fine-structure splitting has not. The paper establishes criteria for optimum LID effects; when using a single-frequency laser the maximum attainable drift velocity is predicted to be 13.8 m/s. Using a proper set of boundary conditions, we find a pressure dependence of LID qualitatively different from the predictions based on previous work. Finally, the influence of the collision model is investigated. We find that LID is independent of the shape of the collision kernel, indicating that a strong-collision model is always valid.
A new light-induced drift effect is discussed in which a white-light source separates a gas mixture containing a single optically active (absorbing) species and a buffer gas which does not interact with the light. A three-level model with one upper level and two closely spaced lower levels is used for the active atoms, and strong collisions with the more abundant surrounding buffer gas atoms are assumed. The intensity spectrum in the vapor (including the effects of hyperfine pumping), and the resulting drift velocity are calculated as a function of optical depth into the vapor.
We address theoretically the effects of a large laser intensity on the phenomenon of light-induced drift. The velocity selectivity of the atom-field interaction decreases due to saturation broadening and this leads to a maximum of the drift velocity as a function of the laser intensity. Analytical expressions for the drift velocity are derived in the case of two-level atoms, assuming a strong collision model. Consequences of this high-field effect are discussed for various manifestations of light-induced drift such as propagation of a soliton in an infinitely long cell, described by the Burgers equation, and collisions of such solitons. The analogy with hydrodynamic shock waves, described by the same Burgers equation, is fruitfully explored. We also address high-field effects on the density distribution produced by light-induced drift in a finite cell. In all these manifestations of light-induced drift the cases of high field and low field show qualitatively different behaviors which are of a complementary nature.