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

Journal of Physics B Atomic Molecular and Optical Physics

Super-radiance from degenerate levels

Решетов Владимир Александрович

Published Nov 14, 1993• 4 citations
Publisher

Abstract

The polarization properties and the temporal shapes of the super-radiance pulses formed on degenerate levels are studied theoretically in a semiclassical approximation. The dependence of the super-radiance pulse polarization on the values of the total angular momenta of resonant levels and on the polarization and area of the pumping pulse is examined in detail. Non-linear equations describing the temporal shapes of the super-radiance pulses with different polarizations are obtained. Some examples with low values of angular momenta of the levels are discussed. It is shown that, in general, the temporal shape of the super-radiance pulse differs from hyperbolic secant.

DOI
10.1088/0953-4075/26/21/012

Related papers

Polarization properties of superradiance from levels with hyperfine structure

Решетов Владимир Александрович

The equations describing the evolution during the linear-emission period of the electric field of superradiance formed by transitions with partially or totally resolved hyperfine structure are obtained in a semiclassical approximation in the case of arbitrary values of electronic angular momenta of the levels and nuclear spin. These equations are used to analyse the polarization properties of superradiance from the levels initially excited from the ground state by the ultra-short linearly polarized laser pulses with small area.

Journal of Physics B Atomic Molecular and Optical Physics•May 14, 1995•1 citation

Polarization properties of coherent signals excited by incoherent light pulses

Решетов Владимир Александрович, Igor V. Yevseyev

The polarizations of photon echoes and superradiance signals formed by incoherent partially polarized exciting pulses are calculated in case of arbitrary values of the resonant level angular momenta. It is shown that the temporal shape of incoherent photon echoes may reproduce the reversed temporal shape of the first exciting pulse.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 26, 1997•0 citations

Level-degeneracy effects in super-radiance theory. Calculations for j=12 to j′=12 dipole transition

A. Crubellier, Marie-Gabrielle Schweighofer

We study here level-degeneracy effects in super-radiance, using the quantum "small-system" model whose interest and limitations are discussed. First, we show that this model allows one to understand the physical origin of these effects and to describe their qualitative influence on the properties of the emitted light. We also present and analyze numerical results obtained for the case of a dipole transition between two degenerate levels of angular momenta \textonehalf{}. We show that in this particular case one can define a basis of collective states which is well adapted to the invariance properties of the master equation. It is then possible to solve the master equation and to compute expectation values for the radiated field (intensity radiated with a given polarization, quantum fluctuations of this intensity) for various initial conditions and for small but already significant values of the number of individual systems. A detailed analysis of these results and a comparison with analogous calculations in the case where the degeneracy is supposed to be removed allows us to estimate the individual influence of the different types of effects (interference effects and the two sorts of competition effects, inhibition and initiation). We also compare the total intensity radiated to the intensity radiated by the same number of two (nondegenerate) level atoms. This comparison can be simply understood if one studies the partition of the population of the collective energy levels between the different states of these levels, and it appears that the most populated states are these which are able to radiate the most. Finally, it is shown how level degeneracy affects the quantum fluctuations of the intensity.

Physical Review A•Nov 1, 1978•24 citations

Quantum fluctuations and self-organization in super-radiance

M. G. Benedict, A. M. Ermolaev, В. А. Малышев +2 more

This chapter focuses on the relation between quantum and semiclassical approaches in super-radiance theory. The semiclassical solution can be regarded only as an ingredient of a convenient scheme for calculating quantum mechanical expectation values. Indeed, at the earliest stages, when the electric field and the polarization have not yet risen above the level of quantum fluctuations, the radiative process is not a classical one and would be greatly disturbed by measurements. The chapter presents some statistical characteristics of the linear stage of super-radiance. Super-radiance may be treated as an amplification of the field generated by quantum fluctuations of the polarization. Another aspect of super-radiance evolution is a build up of coherence both of the radiation field and the atomic polarization. Initially tiny, it grows to a macroscopic size and exhibits the statistics of super-radiance pulses. The parameters characterizing the shape of the pulse vary strongly enough within the ensemble for their root mean square deviations.

CRC Press eBooks•Mar 29, 2018•0 citations

Introduction

M. G. Benedict, A M Ermolaev, V. A. Malyshev +2 more

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book discusses the main features of super-radiance using some simplified models. It presents a review of experimental work on super-radiance. The book also presents a generalization of the Wigner–Weisskopf approach to the N -atom system using a diagram method of non-stationary perturbation theory. It discusses several correlation functions for the field and the polarization, which characterize the coherence properties of super-radiation. The book uses the semiclassical approach to investigate the influence of de-phasing processes on radiation efficiency, or in other words, the influence of homogeneous and inhomogeneous broadening of the spectral line on the dynamics and spectrum of super-radiance. It considers the boundary value problem for the transmission and reflection of short pulses, taking into account the local field correction. Two effects are of special interest: the population-dependent frequency shift and the possibility of mirror-less bistability of ultra-short electromagnetic pulses.

CRC Press eBooks•Mar 29, 2018•0 citations

Effects of diffraction upon super-radiance

M. G. Benedict, A. M. Ermolaev, Viktor A. Malyshev +2 more

This chapter investigates both diffraction and fluctuation effects on super-radiance within the framework of two models. Firstly, the two-dimensional theory of super-radiance of an extended system is developed. Secondly, the chapter considers the super-radiance of a 'sheet of paper' volume. However, quantum fluctuations of the initial polarization give rise to transverse inhomogeneity of atomic and field characteristics, which manifests itself in a change in the shape of the pulse and in the radiation polar diagram. The ringing of the envelope, which is typical of the one-dimensional model, becomes smoother. The super-radiance polar diagram has a ray structure, of which the angular size of individual components (rays) is of the order of the diffraction angle. The angular size of the ray is close to the diffraction angle, and its form changes relatively little from one realization of the initial polarization distribution to another.

CRC Press eBooks•Mar 29, 2018•0 citations
The polarization properties and the temporal shapes of the super-radiance pulses formed on degenerate levels are studied theoretically in a semiclassical approximation. The dependence of the super-radiance pulse polarization on the values of the total angular momenta of resonant levels and on the polarization and area of the pumping pulse is examined in detail. Non-linear equations describing the temporal shapes of the super-radiance pulses with different polarizations are obtained. Some examples with low values of angular momenta of the levels are discussed. It is shown that, in general, the temporal shape of the super-radiance pulse differs from hyperbolic secant.
The equations describing the evolution during the linear-emission period of the electric field of superradiance formed by transitions with partially or totally resolved hyperfine structure are obtained in a semiclassical approximation in the case of arbitrary values of electronic angular momenta of the levels and nuclear spin. These equations are used to analyse the polarization properties of superradiance from the levels initially excited from the ground state by the ultra-short linearly polarized laser pulses with small area.
We study here level-degeneracy effects in super-radiance, using the quantum "small-system" model whose interest and limitations are discussed. First, we show that this model allows one to understand the physical origin of these effects and to describe their qualitative influence on the properties of the emitted light. We also present and analyze numerical results obtained for the case of a dipole transition between two degenerate levels of angular momenta \textonehalf{}. We show that in this particular case one can define a basis of collective states which is well adapted to the invariance properties of the master equation. It is then possible to solve the master equation and to compute expectation values for the radiated field (intensity radiated with a given polarization, quantum fluctuations of this intensity) for various initial conditions and for small but already significant values of the number of individual systems. A detailed analysis of these results and a comparison with analogous calculations in the case where the degeneracy is supposed to be removed allows us to estimate the individual influence of the different types of effects (interference effects and the two sorts of competition effects, inhibition and initiation). We also compare the total intensity radiated to the intensity radiated by the same number of two (nondegenerate) level atoms. This comparison can be simply understood if one studies the partition of the population of the collective energy levels between the different states of these levels, and it appears that the most populated states are these which are able to radiate the most. Finally, it is shown how level degeneracy affects the quantum fluctuations of the intensity.
This chapter focuses on the relation between quantum and semiclassical approaches in super-radiance theory. The semiclassical solution can be regarded only as an ingredient of a convenient scheme for calculating quantum mechanical expectation values. Indeed, at the earliest stages, when the electric field and the polarization have not yet risen above the level of quantum fluctuations, the radiative process is not a classical one and would be greatly disturbed by measurements. The chapter presents some statistical characteristics of the linear stage of super-radiance. Super-radiance may be treated as an amplification of the field generated by quantum fluctuations of the polarization. Another aspect of super-radiance evolution is a build up of coherence both of the radiation field and the atomic polarization. Initially tiny, it grows to a macroscopic size and exhibits the statistics of super-radiance pulses. The parameters characterizing the shape of the pulse vary strongly enough within the ensemble for their root mean square deviations.
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book discusses the main features of super-radiance using some simplified models. It presents a review of experimental work on super-radiance. The book also presents a generalization of the Wigner–Weisskopf approach to the N -atom system using a diagram method of non-stationary perturbation theory. It discusses several correlation functions for the field and the polarization, which characterize the coherence properties of super-radiation. The book uses the semiclassical approach to investigate the influence of de-phasing processes on radiation efficiency, or in other words, the influence of homogeneous and inhomogeneous broadening of the spectral line on the dynamics and spectrum of super-radiance. It considers the boundary value problem for the transmission and reflection of short pulses, taking into account the local field correction. Two effects are of special interest: the population-dependent frequency shift and the possibility of mirror-less bistability of ultra-short electromagnetic pulses.
This chapter investigates both diffraction and fluctuation effects on super-radiance within the framework of two models. Firstly, the two-dimensional theory of super-radiance of an extended system is developed. Secondly, the chapter considers the super-radiance of a 'sheet of paper' volume. However, quantum fluctuations of the initial polarization give rise to transverse inhomogeneity of atomic and field characteristics, which manifests itself in a change in the shape of the pulse and in the radiation polar diagram. The ringing of the envelope, which is typical of the one-dimensional model, becomes smoother. The super-radiance polar diagram has a ray structure, of which the angular size of individual components (rays) is of the order of the diffraction angle. The angular size of the ray is close to the diffraction angle, and its form changes relatively little from one realization of the initial polarization distribution to another.