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

Optics and Spectroscopy

Doppler Frequency Redistribution upon Coherent Photon Emission by Atoms in an Optically Dense Medium

M. N. Araslanova, Н. И. Косарев, M. S. El’berg

Published Nov 1, 2018• 3 citations
Publisher

Abstract

Abstract The problem of transfer of line radiation in sodium vapor under photoexcitation by laser radiation of a resonance line with wavelength λ = 589.6 nm is numerically solved. The influence of Doppler frequency shifts on photon emission coherent in the atomic reference system is taken into account in the formation of an emission line profile using the model of partial frequency redistribution. In the case of a small optical thickness of a medium τ0 ≤ 1, the Doppler frequency redistribution in the laboratory reference system yields higher intensity values in the emission line profile core in comparison with the model of complete frequency redistribution. For an optically dense medium, thermal motion of atoms leads to an increase of reabsorption in the emission line core, and intensity increases in the line wings as compared to the complete redistribution model. The dependence of the Holstein trapping factor on optical thickness is closer to the analytic dependence than the complete redistribution model. This is explained by the fact that the frequencies of emitted photons in the laboratory reference system fall into the spectral profile core, which increases the effects of resonance radiation trapping in a dense medium.

DOI
10.1134/s0030400x18110036

Related papers

Numerical investigation of the escape factor of lithium and sodium vapour at partial frequency redistribution

Н. И. Косарев

The method of numerical simulation was used to study the effective lifetime of the excited level of the resonance transition in sodium and lithium vapour. Taking into account the partial frequency redistribution and the cylindrical geometry of the medium, the rate equations of the population balance of a two-level atom were solved with the equation of radiation transfer. The Biberman–Holstein escape factor was calculated as a function of the optical thickness of vapour for different geometries of the luminescing gas and different models of the frequency redistribution functions. The dependence of the escape factor on the optical thickness investigated experimentally by Romberg and Kunze (J. Quant. Spectrosc. Radiat. Transfer. 1988 39 99) is discussed.

Journal of Physics B Atomic Molecular and Optical Physics•Nov 7, 2008•8 citations

Absorption of resonance radiation and fluorescence of a layer of an atomic gas with thickness of the order of a wavelength

G. Nikogosyan, David G. Sarkisyan, Yu. P. Malakyan

The features of resonance fluorescence and absorption of resonance laser radiation in atomic vapors in a superthin cell with thickness L of the order of a wavelength lambda are investigated theoretically. Taking into account the Fabry-Perot interference effect, it is found that the dependence of the fluorescence and absorption spectra on the ratio L/lambda is substantially different. Coherent spectral narrowing - the Dicke effect - when L=(2n+1)lambda/2 and broadening of the spectral line when L = n lambda (n is a whole number) are observed in the absorption spectra. This effect is absent in the spector of resonance fluorescence in extended media. It is also shown that the processes of saturation and optical pumping significantly alter the spectral line shape as the laser intensity increases; in particular, additional sub-Doppler dips appear at the frequency of the atomic transitions. Calculated curves are given for the D2 lines of ^85Rb atoms. © 2004 Optical Society of America

Journal of Optical Technology•Sep 1, 2004•19 citations

Comments on the problem of anomalous fluorescence of atomic sodium vapor at a wavelength of 589.6 nm

Н. И. Косарев

The problem of the laser-induced fluorescence of sodium vapor at a wavelength of 589.6 nm in the case of photoexcitation of a small volume of the medium by a laser beam has been solved numerically. The photon transfer from the zone of excitation to the periphery in the direction perpendicular to the direction of propagation of the laser radiation leads to a significant extension of the volume with a high density of excited atoms. The influence of this factor on the formation of the resonance fluorescence of sodium vapor is discussed.

Optics and Spectroscopy•Jul 1, 2006•5 citations

Influence of the finite linewidth of the laser radiation spectrum on the shape of the coherent population trapping resonance line in an optically dense medium with a buffer gas

К. А. Баранцев, Е. Н. Попов, A. N. Litvinov

The theory of coherent population trapping resonance is developed for the finite linewidth of the laser radiation spectrum in an optically dense medium of Λ atoms in a cell with a buffer gas. Equations are derived for the atomic density matrix and laser emission spectrum transfer in a cell with working and buffer gases at a finite temperature. The dependence of the quality factor of coherent population trapping resonance on the linewidth of the laser radiation spectrum is studied by measuring transmitted radiation and fluorescence signals.

Journal of Experimental and Theoretical Physics•Nov 1, 2015•14 citations

ЛАЗЕРНАЯ РЕЗОНАНСНАЯ ФЛУОРЕСЦЕНЦИЯ ВРАЩАЮЩЕЙСЯ БАРИЕВОЙ ПЛАЗМЫ

Н. И. Косарев, Елена Васильевна Феськова

We analytically obtained the frequency dependences of the absorption coefficient profile, taking into account the combined influence of the macroscopic motion of matter, Doppler and Voigt mechanisms of spectral line broadening. The effect of rotation of a spherical plasma on the formation of resonant fluorescence by barium ions upon absorption of laser radiation at a wavelength of 455.4 nm was studied. The deformation of the frequency shape of the laser radiation passing through the plasma and the emission spectrum is due to a shift in the absorption coefficient profile and its broadening caused by the rotational motion of the plasma. An increase in the resonant photons escape from the medium stipulated by the broadening of the emission spectrum of the resonance line is predicted.

Журнал прикладной спектроскопии•Jan 29, 2021•0 citations

Redistribution of light frequency by multiple scattering in a resonant atomic vapor

J. C. de Aquino Carvalho, Marcos Oriá, Martine Chevrollier +2 more

The propagation of light in a resonant atomic vapor can a priori be thought of as a multiple scattering process, in which each scattering event redistributes both the direction and the frequency of the photons. Particularly, the frequency redistribution may result in L\'evy flights of photons, directly affecting the transport properties of light in a resonant atomic vapor and turning this propagation into a superdiffusion process. Here, we report on a Monte Carlo simulation developed to study the evolution of the spectrum of the light in a resonant thermal vapor. We observe the gradual change of the spectrum and its convergence towards a regime of complete frequency redistribution as the number of scattering events increases. We also analyze the probability density function of the step length of photons between emissions and reabsorptions in the vapor, which governs the statistics of the light diffusion. We observe two different regimes in the light transport: superdiffusion when the vapor is excited near the line center and normal diffusion for excitation far from the line center. The regime of complete frequency redistribution is not reached for excitation far from resonance even after many absorption and reemission cycles due to correlations between emitted and absorbed frequencies.

arXiv:1506.05683•Physical Review A•May 22, 2015•14 citations
Abstract The problem of transfer of line radiation in sodium vapor under photoexcitation by laser radiation of a resonance line with wavelength λ = 589.6 nm is numerically solved. The influence of Doppler frequency shifts on photon emission coherent in the atomic reference system is taken into account in the formation of an emission line profile using the model of partial frequency redistribution. In the case of a small optical thickness of a medium τ0 ≤ 1, the Doppler frequency redistribution in the laboratory reference system yields higher intensity values in the emission line profile core in comparison with the model of complete frequency redistribution. For an optically dense medium, thermal motion of atoms leads to an increase of reabsorption in the emission line core, and intensity increases in the line wings as compared to the complete redistribution model. The dependence of the Holstein trapping factor on optical thickness is closer to the analytic dependence than the complete redistribution model. This is explained by the fact that the frequencies of emitted photons in the laboratory reference system fall into the spectral profile core, which increases the effects of resonance radiation trapping in a dense medium.
The method of numerical simulation was used to study the effective lifetime of the excited level of the resonance transition in sodium and lithium vapour. Taking into account the partial frequency redistribution and the cylindrical geometry of the medium, the rate equations of the population balance of a two-level atom were solved with the equation of radiation transfer. The Biberman–Holstein escape factor was calculated as a function of the optical thickness of vapour for different geometries of the luminescing gas and different models of the frequency redistribution functions. The dependence of the escape factor on the optical thickness investigated experimentally by Romberg and Kunze (J. Quant. Spectrosc. Radiat. Transfer. 1988 39 99) is discussed.
The features of resonance fluorescence and absorption of resonance laser radiation in atomic vapors in a superthin cell with thickness L of the order of a wavelength lambda are investigated theoretically. Taking into account the Fabry-Perot interference effect, it is found that the dependence of the fluorescence and absorption spectra on the ratio L/lambda is substantially different. Coherent spectral narrowing - the Dicke effect - when L=(2n+1)lambda/2 and broadening of the spectral line when L = n lambda (n is a whole number) are observed in the absorption spectra. This effect is absent in the spector of resonance fluorescence in extended media. It is also shown that the processes of saturation and optical pumping significantly alter the spectral line shape as the laser intensity increases; in particular, additional sub-Doppler dips appear at the frequency of the atomic transitions. Calculated curves are given for the D2 lines of ^85Rb atoms. © 2004 Optical Society of America
The problem of the laser-induced fluorescence of sodium vapor at a wavelength of 589.6 nm in the case of photoexcitation of a small volume of the medium by a laser beam has been solved numerically. The photon transfer from the zone of excitation to the periphery in the direction perpendicular to the direction of propagation of the laser radiation leads to a significant extension of the volume with a high density of excited atoms. The influence of this factor on the formation of the resonance fluorescence of sodium vapor is discussed.
The theory of coherent population trapping resonance is developed for the finite linewidth of the laser radiation spectrum in an optically dense medium of Λ atoms in a cell with a buffer gas. Equations are derived for the atomic density matrix and laser emission spectrum transfer in a cell with working and buffer gases at a finite temperature. The dependence of the quality factor of coherent population trapping resonance on the linewidth of the laser radiation spectrum is studied by measuring transmitted radiation and fluorescence signals.
We analytically obtained the frequency dependences of the absorption coefficient profile, taking into account the combined influence of the macroscopic motion of matter, Doppler and Voigt mechanisms of spectral line broadening. The effect of rotation of a spherical plasma on the formation of resonant fluorescence by barium ions upon absorption of laser radiation at a wavelength of 455.4 nm was studied. The deformation of the frequency shape of the laser radiation passing through the plasma and the emission spectrum is due to a shift in the absorption coefficient profile and its broadening caused by the rotational motion of the plasma. An increase in the resonant photons escape from the medium stipulated by the broadening of the emission spectrum of the resonance line is predicted.
The propagation of light in a resonant atomic vapor can a priori be thought of as a multiple scattering process, in which each scattering event redistributes both the direction and the frequency of the photons. Particularly, the frequency redistribution may result in L\'evy flights of photons, directly affecting the transport properties of light in a resonant atomic vapor and turning this propagation into a superdiffusion process. Here, we report on a Monte Carlo simulation developed to study the evolution of the spectrum of the light in a resonant thermal vapor. We observe the gradual change of the spectrum and its convergence towards a regime of complete frequency redistribution as the number of scattering events increases. We also analyze the probability density function of the step length of photons between emissions and reabsorptions in the vapor, which governs the statistics of the light diffusion. We observe two different regimes in the light transport: superdiffusion when the vapor is excited near the line center and normal diffusion for excitation far from the line center. The regime of complete frequency redistribution is not reached for excitation far from resonance even after many absorption and reemission cycles due to correlations between emitted and absorbed frequencies.