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

Physical Review A

Kerr-free propagation of a near-resonant laser in an atomic vapor

Didier Bénisti, O. Gobert, Michel Comte

Published Jan 30, 2014• 0 citations
Publisher

Abstract

In this paper, we address the propagation of a near resonant laser inside an atomic vapor in the case when, due to the Kerr effect, the laser beam would either self-focus or self-defocus. We show, both theoretically and experimentally, how to get rid of such an alteration in the transverse beam profile without changing any of the characteristics of the laser light under consideration (wavelength, intensity, etc.), nor of the atomic vapor. Moreover, our proposed method offers a lot of control on the beam profile, whose transverse size after propagation may be chosen at will by making use of a second, copropagating laser, whose required wavelength and intensity may be derived analytically.

DOI
10.1103/physreva.89.013849

Related papers

Self-focused light propagation in a fully saturable medium: Theory

Marla L. Dowell, B. D. Paul, Alan C. Gallagher +1 more

A comprehensive model of intense laser light propagation in a fully saturable medium is presented. This model employs the Maxwell-Bloch equations for a two-level atomic system. Light propagating through a medium creates intensity-dependent index of refraction gradients that reduce to a Kerr nonlinearity only for a weak field. When the laser detuning is positive, self-induced index gradients cause the beam to self-focus. Stationary filaments occur when self-focusing exactly balances diffraction. There exists a unique set of two-dimensional fundamental (and higher mode) solutions for which the filament transverse profile (not Gaussian in general) depends on the following quantities: density of saturable absorbers, laser detuning from resonance, laser power, and natural linewidth. (In contrast the Kerr solution does not have a unique filament diameter.) Emphasis will be placed on propagation of Gaussian incident beams; deviations from the stationary solution in either shape or power generally give rise to oscillating spatial patterns, including donutlike profiles, or beam breakup.

Physical Review A•Oct 1, 1995•23 citations

Spatial and temporal behaviors of laser beam propagating in atomic vapor

Keiji Nomaru, Y.-W. Chen, Yasukazu Izawa +2 more

Spatial and temporal behaviors of laser beam propagating in a atomic vapor have been investigated experimentally. The pulse reshapings of frequency‐chirped laser pulses in the near‐resonant atomic vapor have been demonstrated by making use of atomic samarium vapor. Self‐induced transparency and self‐focusing have also been observed by streak camera. Theses results will be compared with numerical or analytical results in this paper.

AIP conference proceedings•Jan 1, 1996•0 citations

Light self-trapping in a large cloud of cold atoms

G. Labeyrie, U. Bortolozzo

We show that, for a near-resonant propagating beam, a large cloud of cold 87Rb atoms acts as a saturable Kerr medium and produces self-trapping of light. By side fluorescence imaging we monitor the transverse size of the beam and, depending on the sign of the laser detuning with respect to the atomic transition, we observe self-focusing or -defocusing, with the waist remaining stationary for an appropriate choice of parameters. We analyze our observations by using numerical simulations based on a simple 2-level atom model.

•Jan 1, 2013•4 citations

Instabilities in the Propagation of Laser Beams Through Atomic Vapors

Robert W. Boyd, Daniel J. Gauthier, Michelle S. Malcuit

There are several nonlinear optical processes that can lead to instabilities in a laser beam as it propagates through a nonlinear optical medium. Self focusing effects, for instance, can lead to the growth of new spatial frequency components in a laser beam. A laser beam can also be unstable to the growth of new spectral components. Stimulated Raman scattering is a well-known example of a process that can lead to this sort of instability. In this paper, we present the results of a series of experiments on the somewhat different instabilities that occur for the case of the propagation of a laser beam through an atomic vapor. We find that these instabilities become particularly pronounced when the frequency of the incident laser is near to that of a one- or two-photon resonance of the atom. In either case, we find that the laser beam is unstable to the growth of new frequency components, and that in general these new frequencies are not emitted collinearly with the incident laser. These instabilities are important because they place a limit on the laser intensity that can be used to drive nonlinear optical processes.

International Meeting on Instabilities and Dynamics of Lasers and Nonlinear Optical Systems•Jan 1, 1985•0 citations

Light self-trapping in a large cloud of cold atoms

G. Labeyrie, U. Bortolozzo

We show that, for a near-resonant propagating beam, a large cloud of cold Rb87 atoms acts as a saturable Kerr medium and produces self-trapping of light. By side fluorescence imaging, we monitor the transverse size of the beam and, depending on the sign of the laser detuning with respect to the atomic transition, we observe self-focusing or self-defocusing, with the waist remaining stationary for an appropriate choice of parameters. We analyze our observations by using numerical simulations based on a simple two-level atom model.

arXiv:1104.1916•Optics Letters•May 31, 2011•8 citations

Spatial distortions of laser pulses in coherent on-resonance propagation: Small-scale self-focusing

Jacques de Lamare, Ph.J. Kupecek, Michel Comte

We present a quantitative model for coherent on-resonance small-scale self-focusing of laser pulses in atomic media. A vapor-induced diaphragm effect at the edge of the pulse generates a pattern of diffraction rings that modulates the initial transverse profile of the pulse. Practically, because of the spatial asymmetry of the original pulse, this diffraction pattern is perturbed and dots appear superimposed upon the rings. A large-scale self-focusing phenomenon is then initiated from each individual dot and the global transverse energy profile of the pulse evolves in a hot-spot pattern. This final pattern is characteristic of what is usually called small-scale self-focusing. Our theoretical predictions are compared with both the results of an experiment on a $^{169}\mathrm{Tm}$ vapor and the predictions of existing models.

Physical Review A•May 1, 1995•4 citations
In this paper, we address the propagation of a near resonant laser inside an atomic vapor in the case when, due to the Kerr effect, the laser beam would either self-focus or self-defocus. We show, both theoretically and experimentally, how to get rid of such an alteration in the transverse beam profile without changing any of the characteristics of the laser light under consideration (wavelength, intensity, etc.), nor of the atomic vapor. Moreover, our proposed method offers a lot of control on the beam profile, whose transverse size after propagation may be chosen at will by making use of a second, copropagating laser, whose required wavelength and intensity may be derived analytically.
A comprehensive model of intense laser light propagation in a fully saturable medium is presented. This model employs the Maxwell-Bloch equations for a two-level atomic system. Light propagating through a medium creates intensity-dependent index of refraction gradients that reduce to a Kerr nonlinearity only for a weak field. When the laser detuning is positive, self-induced index gradients cause the beam to self-focus. Stationary filaments occur when self-focusing exactly balances diffraction. There exists a unique set of two-dimensional fundamental (and higher mode) solutions for which the filament transverse profile (not Gaussian in general) depends on the following quantities: density of saturable absorbers, laser detuning from resonance, laser power, and natural linewidth. (In contrast the Kerr solution does not have a unique filament diameter.) Emphasis will be placed on propagation of Gaussian incident beams; deviations from the stationary solution in either shape or power generally give rise to oscillating spatial patterns, including donutlike profiles, or beam breakup.
We show that, for a near-resonant propagating beam, a large cloud of cold 87Rb atoms acts as a saturable Kerr medium and produces self-trapping of light. By side fluorescence imaging we monitor the transverse size of the beam and, depending on the sign of the laser detuning with respect to the atomic transition, we observe self-focusing or -defocusing, with the waist remaining stationary for an appropriate choice of parameters. We analyze our observations by using numerical simulations based on a simple 2-level atom model.
There are several nonlinear optical processes that can lead to instabilities in a laser beam as it propagates through a nonlinear optical medium. Self focusing effects, for instance, can lead to the growth of new spatial frequency components in a laser beam. A laser beam can also be unstable to the growth of new spectral components. Stimulated Raman scattering is a well-known example of a process that can lead to this sort of instability. In this paper, we present the results of a series of experiments on the somewhat different instabilities that occur for the case of the propagation of a laser beam through an atomic vapor. We find that these instabilities become particularly pronounced when the frequency of the incident laser is near to that of a one- or two-photon resonance of the atom. In either case, we find that the laser beam is unstable to the growth of new frequency components, and that in general these new frequencies are not emitted collinearly with the incident laser. These instabilities are important because they place a limit on the laser intensity that can be used to drive nonlinear optical processes.
We show that, for a near-resonant propagating beam, a large cloud of cold Rb87 atoms acts as a saturable Kerr medium and produces self-trapping of light. By side fluorescence imaging, we monitor the transverse size of the beam and, depending on the sign of the laser detuning with respect to the atomic transition, we observe self-focusing or self-defocusing, with the waist remaining stationary for an appropriate choice of parameters. We analyze our observations by using numerical simulations based on a simple two-level atom model.
We present a quantitative model for coherent on-resonance small-scale self-focusing of laser pulses in atomic media. A vapor-induced diaphragm effect at the edge of the pulse generates a pattern of diffraction rings that modulates the initial transverse profile of the pulse. Practically, because of the spatial asymmetry of the original pulse, this diffraction pattern is perturbed and dots appear superimposed upon the rings. A large-scale self-focusing phenomenon is then initiated from each individual dot and the global transverse energy profile of the pulse evolves in a hot-spot pattern. This final pattern is characteristic of what is usually called small-scale self-focusing. Our theoretical predictions are compared with both the results of an experiment on a 169Tm^{169}\mathrm{Tm}169Tm vapor and the predictions of existing models.