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

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

Rostislav M. Arkhipov, A. V. Pakhomov

Published May 1, 2017• 2 citations
Publisher

Abstract

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.

DOI
10.1134/s0030400x17050034

Related papers

Emission of a spatially modulated resonant medium excited with superluminal velocity

Mikhail V. Arkhipov, Rostislav M. Arkhipov, Yu. A. Tolmachev

Specific characteristics of the radiation of a resonant medium excited by an ultrashort light pulse propagating through the medium with a superluminal velocity are considered. The medium is assumed to consist of identical linear harmonic oscillators with a spatial density periodically modulated along the direction of propagation of the superluminal excitation. The field of radiation of the resonant medium under these conditions is calculated. It is shown that, under the superluminal excitation, the radiation spectrum of the medium shows, along with the fundamental frequency of the oscillators, new frequencies that depend on the spatial frequency of the distribution of oscillators and on the angle of observation. Possible application of the effect is discussed.

Optics and Spectroscopy•Feb 1, 2012•12 citations

Controlling the Radiation Parameters of a Resonant Medium Excited by a Sequence of Ultrashort Superluminal Pulses

Rostislav M. Arkhipov, Mikhail V. Arkhipov, P. Belov +2 more

We investigate the possibility of controlling the radiation parameters of a spatially periodic one-dimensional medium consisting of classical harmonic oscillators by means of a sequence of ultrashort pulses that propagate through the medium with a superluminal velocity. We show that, in the spectrum of the transient process, in addition to the radiation at a resonant frequency of oscillators, new frequencies arise that depend on the period of the spatial distribution of the oscillator density, the excitation velocity, and the angle of observation. We have examined in detail the case of excitation of the medium by a periodic sequence of ultrashort pulses that travel with a superluminal velocity. We show that it is possible to excite oscillations of complex shapes and to control the radiation parameters of the resonant medium by changing the relationship between the pulse repetition rate, the medium resonant frequency, and the new frequency.

Optics and Spectroscopy•Mar 1, 2016•5 citations

Transient radiation from a ring resonant medium excited by an ultrashort superluminal pulse

Rostislav M. Arkhipov, Mikhail V. Arkhipov, Ihar Babushkin +1 more

We report some specific features of transient radiation from a periodic spatially modulated one-dimensional medium with a resonant response upon excitation by an ultrashort pulse. The case of ring geometry (with particle density distributed along the ring according to the harmonic law) is considered. It is shown that the spectrum of scattered radiation contains (under both linear and nonlinear interaction), along with the frequency of intrinsic resonance of the medium, a new frequency, which depends on the pulse velocity and the spatial modulation period. The case of superluminal motion of excitation, when the Cherenkov effect manifests itself, is also analysed.

Quantum Electronics•Jun 26, 2015•11 citations

Radiation of a resonant medium excited by few-cycle optical pulses at superluminal velocity

Rostislav M. Arkhipov, A. V. Pakhomov, Mikhail V. Arkhipov +3 more

Abstract Recent progress in generation of optical pulses of durations comparable to one optical cycle has presented great opportunities for studies of the fundamental processes in matter as well as time-resolved spectroscopy of ultrafast processes in nonlinear media. It opened up a new area of research in modern ultrafast nonlinear optics and led to appearance of the attosecond science. In parallel, a new research area related to emission from resonant media excited by superluminally propagating ultrashort bursts of electromagnetic radiation has been actively developed over the last few years. In this paper, we review our recent results on theoretical analysis of the Cherenkov-type radiation of a resonant medium excited by few-cycle optical pulses propagating at superluminal velocity. This situation can be realized when an electromagnetic pulse with a plane wavefront incidents on a straight string of resonant atoms or a spot of light rotates at very large angular frequency and excites a distant circular string of resonant dipoles. Theoretical analysis revealed some unusual and remarkable features of the Cherenkov radiation generated in this case. This radiation arises in a transient regime which leads to the occurrence of new frequencies in the radiation spectrum. Analysis of the characteristics of this radiation can be used for the study of the resonant structure properties. In addition, a nonlinear resonant medium excited at superluminal velocity can emit unipolar optical pulses, which can be important in ultrafast control of wave-packet dynamics of matter. Specifics of the few-cycle pulse-driven optical response of a resonant medium composed of linear and nonlinear oscillators is discussed.

Laser Physics•Apr 3, 2017•21 citations

Particular features of the emission of radiation by a superluminally excited Raman-active medium

Rostislav M. Arkhipov

Particular features of the emission of radiation by a Raman-active medium excited by a sequence of ultrashort superluminal pulses have been studied theoretically. It is shown that such an excitation gives rise to the possibility of obtaining unipolar rectangular videopulses the duration and amplitude of which depend on the velocity of propagation of the excitation over the medium.

Optics and Spectroscopy•May 1, 2016•15 citations

Superluminal to Subluminal Transition in the Pulse Propagation in a Resonantly Absorbing Medium

Md. Aminul Islam Talukder, Yoshimitsu Amagishi, Makoto Tomita

We have examined the propagation of femtosecond laser pulses in an absorbing dye solution through a short to a long range of propagation distance. The transmitted pulses show strong spectral shift and a superluminal to subluminal transition in the propagation velocity keeping its initial shape almost intact. It is verified that the peak velocity is well described by a modified group velocity v(S) defined within the framework of the saddle-point method as well as by a recent prediction of the net group delay of surviving frequency.

Physical Review Letters•Apr 16, 2001•91 citations
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.
Specific characteristics of the radiation of a resonant medium excited by an ultrashort light pulse propagating through the medium with a superluminal velocity are considered. The medium is assumed to consist of identical linear harmonic oscillators with a spatial density periodically modulated along the direction of propagation of the superluminal excitation. The field of radiation of the resonant medium under these conditions is calculated. It is shown that, under the superluminal excitation, the radiation spectrum of the medium shows, along with the fundamental frequency of the oscillators, new frequencies that depend on the spatial frequency of the distribution of oscillators and on the angle of observation. Possible application of the effect is discussed.
We investigate the possibility of controlling the radiation parameters of a spatially periodic one-dimensional medium consisting of classical harmonic oscillators by means of a sequence of ultrashort pulses that propagate through the medium with a superluminal velocity. We show that, in the spectrum of the transient process, in addition to the radiation at a resonant frequency of oscillators, new frequencies arise that depend on the period of the spatial distribution of the oscillator density, the excitation velocity, and the angle of observation. We have examined in detail the case of excitation of the medium by a periodic sequence of ultrashort pulses that travel with a superluminal velocity. We show that it is possible to excite oscillations of complex shapes and to control the radiation parameters of the resonant medium by changing the relationship between the pulse repetition rate, the medium resonant frequency, and the new frequency.
We report some specific features of transient radiation from a periodic spatially modulated one-dimensional medium with a resonant response upon excitation by an ultrashort pulse. The case of ring geometry (with particle density distributed along the ring according to the harmonic law) is considered. It is shown that the spectrum of scattered radiation contains (under both linear and nonlinear interaction), along with the frequency of intrinsic resonance of the medium, a new frequency, which depends on the pulse velocity and the spatial modulation period. The case of superluminal motion of excitation, when the Cherenkov effect manifests itself, is also analysed.
Abstract Recent progress in generation of optical pulses of durations comparable to one optical cycle has presented great opportunities for studies of the fundamental processes in matter as well as time-resolved spectroscopy of ultrafast processes in nonlinear media. It opened up a new area of research in modern ultrafast nonlinear optics and led to appearance of the attosecond science. In parallel, a new research area related to emission from resonant media excited by superluminally propagating ultrashort bursts of electromagnetic radiation has been actively developed over the last few years. In this paper, we review our recent results on theoretical analysis of the Cherenkov-type radiation of a resonant medium excited by few-cycle optical pulses propagating at superluminal velocity. This situation can be realized when an electromagnetic pulse with a plane wavefront incidents on a straight string of resonant atoms or a spot of light rotates at very large angular frequency and excites a distant circular string of resonant dipoles. Theoretical analysis revealed some unusual and remarkable features of the Cherenkov radiation generated in this case. This radiation arises in a transient regime which leads to the occurrence of new frequencies in the radiation spectrum. Analysis of the characteristics of this radiation can be used for the study of the resonant structure properties. In addition, a nonlinear resonant medium excited at superluminal velocity can emit unipolar optical pulses, which can be important in ultrafast control of wave-packet dynamics of matter. Specifics of the few-cycle pulse-driven optical response of a resonant medium composed of linear and nonlinear oscillators is discussed.
We have examined the propagation of femtosecond laser pulses in an absorbing dye solution through a short to a long range of propagation distance. The transmitted pulses show strong spectral shift and a superluminal to subluminal transition in the propagation velocity keeping its initial shape almost intact. It is verified that the peak velocity is well described by a modified group velocity v(S) defined within the framework of the saddle-point method as well as by a recent prediction of the net group delay of surviving frequency.