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

Controlling the parameters of short-wavelength radiation pulses using the interference of transitions to a continuum

Yu. I. Geller, D. E. Sovkov, A. T. Hakim’yanov

Published Oct 1, 2003• 4 citations
Publisher

Abstract

Specific features of the propagation of light pulses with frequency lying in the range of autoionization resonances of the medium are analyzed. It is shown that the interference nature of the autoionization spectra makes it possible to combine a strong frequency dispersion of the refractive index with small absorption when the radiation frequency approaches the spectral range of the "transparency window" of an isolated resonance or of a series of overlapped autoionization resonances. This allows one to control the time delay of the pulses and their group velocity. Depending on the parameters of the medium, the pulse group velocity may be maximally reduced by a factor of 10 4 –10 5 .

DOI
10.1134/1.1621447

Related papers

Light drag in moving media with a high frequency dispersion

Yu. I. Heller

The influence of spectral interference of various nature on the effects of radiation drag is studied using as examples electromagnetically induced transparency in pure discrete atomic transitions and the transparency windows of autoionization resonances of gaseous media. The analysis is performed using the Maxwell equations and taking into account the equivalence of the corresponding spatial dispersion of a substance and the optical effects caused by uniform motion. The realization conditions of the drag coefficients in the Lorentz and Laub forms are found from the exact dispersion equations obtained. A direct relation between the monochromatic radiation drag coefficient and the decrease in the pulsed radiation group velocity due to high frequency dispersion of the resonant refractive index is found. The known experimental data on ultraslow light pulses indicate the possibility of interference enhancement of the light drag effect by a factor of 10 6 -10 7 .

Optics and Spectroscopy•Nov 1, 2006•1 citation

Light slowing-down effects caused by nonlinear interactions of radiations in two-level systems

Yu. I. Heller, A. V. Sharypov

The effect of slowing down pulses of probe radiation in a medium consisting of two-level quantum systems whose longitudinal and transverse relaxation times strongly differ is studied. The conditions for the occurrence of “slow light” in a transparency window are obtained. Regimes are discovered in which the medium becomes transparent or amplifies the probe radiation, with the high dispersion of the refractive index being conserved. The parameters at which the delay time of the probe radiation reaches a maximum or the group velocity of this radiation decreases to a maximal possible value under the condition of exact resonance with the strong field are found.

Optics and Spectroscopy•Feb 1, 2009•3 citations

Interference enhancement of resonant magneto-optical effects

Yu. I. Heller

The influence of spectral interference of different nature on resonant Faraday rotation is studied using as examples the effect of electromagnetically induced transparency in pure discrete atomic transitions and the transparency windows of autoionization resonances of gaseous media. A common numerical criterion for a substantial effect of spectral interference and coherence of atomic transitions on magneto-optical phenomena is established. A direct relationship between the polarization ellipse rotation angle of cw monochromatic light and reduction of the light pulse group velocity resulting from a strong frequency dispersion of the resonant refractive index is found. The known experimental data on ultraslow light pulses indicate the possibility of interference enhancement of the Faraday effect by a factor of 10 6 −10 7 .

Optics and Spectroscopy•Feb 1, 2006•1 citation

From refractive index to stopped light

Jarosław Zaremba

Investigations of controlled modifications of dispersive properties of atomic media and of propagation of short laser pulses have recently become a dynamically developing field of theoretical and experimental researches. In this lecture a brief overview is presented of basic physical phenomena underlying modifications of a group velocity of a pulse propagating in an optically modified medium. In particular, the possibilities of slowing down this velocity to zero and of retrieving the stopped pulse are discussed.

ICTON Mediterranean Winter Conference (ICTON-MW)•Dec 1, 2009•0 citations

Emission of radiation by a resonance medium excited with a variable superluminal velocity

Rostislav M. Arkhipov, A. V. Pakhomov

Specific properties of the radiation emitted by a spatially modulated resonance medium excited by an ultrashort light pulse propagating through the medium at a variable superluminal velocity are analyzed. In so doing, frequencies different from that of the resonance transition of the medium may appear in the emission spectrum. It is demonstrated that, in contrast to an earlier studied case of medium excitation at constant velocity, variation of the excitation velocity leads to generation of a spectral continuum, the boundaries of which are determined by the range of variation of the medium-excitation velocity.

Optics and Spectroscopy•May 1, 2017•2 citations

Propagation dynamics in an autoionization medium

Emmanuel Paspalakis, Niels J. Kylstra, P. L. Knight

We demonstrate that an autoionizing medium can, under specific conditions, become transparent to a short laser pulse propagating in the medium. The interference that leads to transparency is intrinsic to the system and relies on the establishment of a ``dark,'' or ``trapped,'' state that exists as a consequence of Fano interference between direct and resonant photoionization processes.

Physical Review A•Jul 1, 1999•31 citations
Specific features of the propagation of light pulses with frequency lying in the range of autoionization resonances of the medium are analyzed. It is shown that the interference nature of the autoionization spectra makes it possible to combine a strong frequency dispersion of the refractive index with small absorption when the radiation frequency approaches the spectral range of the "transparency window" of an isolated resonance or of a series of overlapped autoionization resonances. This allows one to control the time delay of the pulses and their group velocity. Depending on the parameters of the medium, the pulse group velocity may be maximally reduced by a factor of 10 4 –10 5 .
The influence of spectral interference of various nature on the effects of radiation drag is studied using as examples electromagnetically induced transparency in pure discrete atomic transitions and the transparency windows of autoionization resonances of gaseous media. The analysis is performed using the Maxwell equations and taking into account the equivalence of the corresponding spatial dispersion of a substance and the optical effects caused by uniform motion. The realization conditions of the drag coefficients in the Lorentz and Laub forms are found from the exact dispersion equations obtained. A direct relation between the monochromatic radiation drag coefficient and the decrease in the pulsed radiation group velocity due to high frequency dispersion of the resonant refractive index is found. The known experimental data on ultraslow light pulses indicate the possibility of interference enhancement of the light drag effect by a factor of 10 6 -10 7 .
The effect of slowing down pulses of probe radiation in a medium consisting of two-level quantum systems whose longitudinal and transverse relaxation times strongly differ is studied. The conditions for the occurrence of “slow light” in a transparency window are obtained. Regimes are discovered in which the medium becomes transparent or amplifies the probe radiation, with the high dispersion of the refractive index being conserved. The parameters at which the delay time of the probe radiation reaches a maximum or the group velocity of this radiation decreases to a maximal possible value under the condition of exact resonance with the strong field are found.
The influence of spectral interference of different nature on resonant Faraday rotation is studied using as examples the effect of electromagnetically induced transparency in pure discrete atomic transitions and the transparency windows of autoionization resonances of gaseous media. A common numerical criterion for a substantial effect of spectral interference and coherence of atomic transitions on magneto-optical phenomena is established. A direct relationship between the polarization ellipse rotation angle of cw monochromatic light and reduction of the light pulse group velocity resulting from a strong frequency dispersion of the resonant refractive index is found. The known experimental data on ultraslow light pulses indicate the possibility of interference enhancement of the Faraday effect by a factor of 10 6 −10 7 .
Investigations of controlled modifications of dispersive properties of atomic media and of propagation of short laser pulses have recently become a dynamically developing field of theoretical and experimental researches. In this lecture a brief overview is presented of basic physical phenomena underlying modifications of a group velocity of a pulse propagating in an optically modified medium. In particular, the possibilities of slowing down this velocity to zero and of retrieving the stopped pulse are discussed.
Specific properties of the radiation emitted by a spatially modulated resonance medium excited by an ultrashort light pulse propagating through the medium at a variable superluminal velocity are analyzed. In so doing, frequencies different from that of the resonance transition of the medium may appear in the emission spectrum. It is demonstrated that, in contrast to an earlier studied case of medium excitation at constant velocity, variation of the excitation velocity leads to generation of a spectral continuum, the boundaries of which are determined by the range of variation of the medium-excitation velocity.