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 Journal of Modern Physics Conference Series

Coherent specular reflection of resonant light from a dense ensemble of motionless point-like scatters in a slab geometry

A. S. Kuraptsev, Igor M. Sokolov, Ya. A. Fofanov

Published Jan 1, 2016• 12 citations
Publisher

Abstract

We analyze resonant light scattering from a dense and disordered ensemble of motionless point-like scatters with uniform (on average) spatial distribution of the density. The average interatomic distance is considered comparable with the resonant wavelength and the mean free path of photon. The inhomogeneity of dipole-dipole interaction near the surface is discussed. Angular distribution of the light scattered from a medium in a slab geometry is calculated. The total reflected light power [Formula: see text] and the reflectivity [Formula: see text] depending on the optical thickness of a medium [Formula: see text] are analyzed. It is shown that in the case of small optical thickness ([Formula: see text]) [Formula: see text] and [Formula: see text]. With further increasing of the optical thickness we observe oscillations of the dependencies [Formula: see text] and [Formula: see text]. The attenuation coefficient of these oscillations is discussed.

DOI
10.1142/s2010194516601411

Related papers

Reflection of resonant light from a plane surface of an ensemble of motionless point scatters: Quantum microscopic approach

A. S. Kuraptsev, Igor M. Sokolov

On the basis of general theoretical results developed previously in [JETP 112, 246 (2011)], we analyze the reflection of quasiresonant light from a plane surface of dense and disordered ensemble of motionless point scatters. Angle distribution of the scattered light is calculated both for $s$ and $p$ polarizations of the probe radiation. The ratio between coherent and incoherent (diffuse) components of scattered light is calculated. We analyze the contributions of scatters located at different distances from the surface and determine on this background the thickness of surface layer responsible for reflected beam generation. The inhomogeneity of dipole-dipole interaction near the surface is discussed. We study also dependence of total reflected light power on the incidence angle and compare the results of the microscopic approach with predictions of the Fresnel reflection theory. The calculations are performed for different densities of scatters and different frequencies of a probe radiation.

arXiv:1601.03573•Physical Review A•May 13, 2015•42 citations

Light transmission of the dense and cold atomic ensembles

Igor M. Sokolov

On the basis of the general theoretical results developed previously (Sokolov et al 2011 J. Exp. Theor. Phys. 112 246) we calculate the light transmission coefficient of a disordered dense ensemble of motionless atomic scatterers. We analyze dependence of this coefficient on thickness of the ensemble as well as on frequency of the light. This analysis shows no manifestation of light localization effects, even in those parameter regimes where the Ioffe–Regel criterion of strong localization is satisfied. An analogous calculation made in the framework of scalar approximation when the vector character of light is neglected demonstrates strong localization under some conditions.

Laser Physics•May 1, 2015•6 citations

Coherent Scattering of Near-Resonant Light by a Dense Microscopic Cold Atomic Cloud

Stephan Jennewein, Mondher Besbes, Nick J. Schilder +6 more

We measure the coherent scattering of light by a cloud of laser-cooled atoms with a size comparable to the wavelength of light. By interfering a laser beam tuned near an atomic resonance with the field scattered by the atoms, we observe a resonance with a redshift, a broadening, and a saturation of the extinction for increasing atom numbers. We attribute these features to enhanced light-induced dipole-dipole interactions in a cold, dense atomic ensemble that result in a failure of standard predictions such as the "cooperative Lamb shift". The description of the atomic cloud by a mean-field model based on the Lorentz-Lorenz formula that ignores scattering events where light is scattered recurrently by the same atom and by a microscopic discrete dipole model that incorporates these effects lead to progressively closer agreement with the observations, despite remaining differences.

arXiv:1510.08041•Physical Review Letters•Jun 8, 2016•131 citations

Coherent backscattering of light by an inhomogeneous cloud of cold atoms

G. Labeyrie, Dominique Delande, Cord Axel Müller +2 more

When a quasiresonant laser beam illuminates an optically thick cloud of laser-cooled rubidium atoms, the average diffuse intensity reflected off the sample is enhanced in a narrow angular range around the direction of exact backscattering. This phenomenon is known as coherent backscattering (CBS). By detuning the laser from resonance, we are able to modify the light scattering mean-free path inside the sample and we record accordingly the variations of the CBS cone shape. We then compare the experimental data with theoretical calculations and Monte Carlo simulations including the effect of the light polarization and of the internal structure of the atoms. We confirm that the internal structure strongly affects the enhancement factor of the cone and we show that the unusual shape of the atomic medium---approximately a spherically-symmetric, Gaussian density profile---strongly affects the width and shape of the cone.

Physical Review A•Mar 27, 2003•47 citations

Homogenization of an ensemble of interacting resonant scatterers

Nick J. Schilder, Christophe Sauvan, Yvan R. P. Sortais +2 more

We study theoretically the concept of homogenization in optics using an ensemble of randomly distributed resonant stationary atoms with density $\ensuremath{\rho}$. The ensemble is dense enough for the usual condition for homogenization, viz. $\ensuremath{\rho}{\ensuremath{\lambda}}^{3}\ensuremath{\gg}1$, to be reached. Introducing the coherent and incoherent scattered powers, we define two criteria to define the homogenization regime. We find that when the excitation field is tuned in a broad frequency range around the resonance, neither of the criteria for homogenization is fulfilled, meaning that the condition $\ensuremath{\rho}{\ensuremath{\lambda}}^{3}\ensuremath{\gg}1$ is not sufficient to characterize the homogenized regime around the atomic resonance. We interpret these results as a consequence of the light-induced dipole-dipole interactions between the atoms, which implies a description of scattering in terms of collective modes rather than as a sequence of individual scattering events. Finally, we show that, although homogenization can never be reached for a dense ensemble of randomly positioned laser-cooled atoms around resonance, it becomes possible if one introduces spatial correlations in the positions of the atoms or nonradiative losses, such as would be the case for organic molecules or quantum dots coupled to a phonon bath.

arXiv:1706.01235•Physical Review A•Jul 13, 2017•21 citations

Modified dipole-dipole interaction and dissipation in an atomic ensemble near surfaces

Ryan Jones, Jemma A. Needham, Igor Lesanovsky +2 more

We study how the radiative properties of a dense ensemble of atoms can be modified when they are placed near or between metallic or dielectric surfaces. If the average separation between the atoms is comparable or smaller than the wavelength of the scattered photons, the coupling to the radiation field induces long-range coherent interactions based on the interatomic exchange of virtual photons. Moreover, the incoherent scattering of photons back to the electromagnetic field is known to be a many-body process, characterized by the appearance of superradiant and subradiant emission modes. By changing the radiation field properties, in this case by considering a layered medium where the atoms are near metallic or dielectric surfaces, these scattering properties can be dramatically modified. We perform a detailed study of these effects, with focus on experimentally relevant parameter regimes. We finish with a specific application in the context of quantum information storage, where the presence of a nearby surface is shown to increase the storage time of an atomic excitation that is transported across a one-dimensional chain.

arXiv:1803.06309•Physical Review A•May 29, 2018•32 citations
We analyze resonant light scattering from a dense and disordered ensemble of motionless point-like scatters with uniform (on average) spatial distribution of the density. The average interatomic distance is considered comparable with the resonant wavelength and the mean free path of photon. The inhomogeneity of dipole-dipole interaction near the surface is discussed. Angular distribution of the light scattered from a medium in a slab geometry is calculated. The total reflected light power [Formula: see text] and the reflectivity [Formula: see text] depending on the optical thickness of a medium [Formula: see text] are analyzed. It is shown that in the case of small optical thickness ([Formula: see text]) [Formula: see text] and [Formula: see text]. With further increasing of the optical thickness we observe oscillations of the dependencies [Formula: see text] and [Formula: see text]. The attenuation coefficient of these oscillations is discussed.
On the basis of general theoretical results developed previously in [JETP 112, 246 (2011)], we analyze the reflection of quasiresonant light from a plane surface of dense and disordered ensemble of motionless point scatters. Angle distribution of the scattered light is calculated both for sss and ppp polarizations of the probe radiation. The ratio between coherent and incoherent (diffuse) components of scattered light is calculated. We analyze the contributions of scatters located at different distances from the surface and determine on this background the thickness of surface layer responsible for reflected beam generation. The inhomogeneity of dipole-dipole interaction near the surface is discussed. We study also dependence of total reflected light power on the incidence angle and compare the results of the microscopic approach with predictions of the Fresnel reflection theory. The calculations are performed for different densities of scatters and different frequencies of a probe radiation.
On the basis of the general theoretical results developed previously (Sokolov et al 2011 J. Exp. Theor. Phys. 112 246) we calculate the light transmission coefficient of a disordered dense ensemble of motionless atomic scatterers. We analyze dependence of this coefficient on thickness of the ensemble as well as on frequency of the light. This analysis shows no manifestation of light localization effects, even in those parameter regimes where the Ioffe–Regel criterion of strong localization is satisfied. An analogous calculation made in the framework of scalar approximation when the vector character of light is neglected demonstrates strong localization under some conditions.
We measure the coherent scattering of light by a cloud of laser-cooled atoms with a size comparable to the wavelength of light. By interfering a laser beam tuned near an atomic resonance with the field scattered by the atoms, we observe a resonance with a redshift, a broadening, and a saturation of the extinction for increasing atom numbers. We attribute these features to enhanced light-induced dipole-dipole interactions in a cold, dense atomic ensemble that result in a failure of standard predictions such as the "cooperative Lamb shift". The description of the atomic cloud by a mean-field model based on the Lorentz-Lorenz formula that ignores scattering events where light is scattered recurrently by the same atom and by a microscopic discrete dipole model that incorporates these effects lead to progressively closer agreement with the observations, despite remaining differences.
When a quasiresonant laser beam illuminates an optically thick cloud of laser-cooled rubidium atoms, the average diffuse intensity reflected off the sample is enhanced in a narrow angular range around the direction of exact backscattering. This phenomenon is known as coherent backscattering (CBS). By detuning the laser from resonance, we are able to modify the light scattering mean-free path inside the sample and we record accordingly the variations of the CBS cone shape. We then compare the experimental data with theoretical calculations and Monte Carlo simulations including the effect of the light polarization and of the internal structure of the atoms. We confirm that the internal structure strongly affects the enhancement factor of the cone and we show that the unusual shape of the atomic medium---approximately a spherically-symmetric, Gaussian density profile---strongly affects the width and shape of the cone.
We study theoretically the concept of homogenization in optics using an ensemble of randomly distributed resonant stationary atoms with density $\ensuremath{\rho}$. The ensemble is dense enough for the usual condition for homogenization, viz. $\ensuremath{\rho}{\ensuremath{\lambda}}^{3}\ensuremath{\gg}1$, to be reached. Introducing the coherent and incoherent scattered powers, we define two criteria to define the homogenization regime. We find that when the excitation field is tuned in a broad frequency range around the resonance, neither of the criteria for homogenization is fulfilled, meaning that the condition $\ensuremath{\rho}{\ensuremath{\lambda}}^{3}\ensuremath{\gg}1$ is not sufficient to characterize the homogenized regime around the atomic resonance. We interpret these results as a consequence of the light-induced dipole-dipole interactions between the atoms, which implies a description of scattering in terms of collective modes rather than as a sequence of individual scattering events. Finally, we show that, although homogenization can never be reached for a dense ensemble of randomly positioned laser-cooled atoms around resonance, it becomes possible if one introduces spatial correlations in the positions of the atoms or nonradiative losses, such as would be the case for organic molecules or quantum dots coupled to a phonon bath.
We study how the radiative properties of a dense ensemble of atoms can be modified when they are placed near or between metallic or dielectric surfaces. If the average separation between the atoms is comparable or smaller than the wavelength of the scattered photons, the coupling to the radiation field induces long-range coherent interactions based on the interatomic exchange of virtual photons. Moreover, the incoherent scattering of photons back to the electromagnetic field is known to be a many-body process, characterized by the appearance of superradiant and subradiant emission modes. By changing the radiation field properties, in this case by considering a layered medium where the atoms are near metallic or dielectric surfaces, these scattering properties can be dramatically modified. We perform a detailed study of these effects, with focus on experimentally relevant parameter regimes. We finish with a specific application in the context of quantum information storage, where the presence of a nearby surface is shown to increase the storage time of an atomic excitation that is transported across a one-dimensional chain.