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

Physical Review Letters

Doppler Beats in Superradiance

M. Groß, J. M. Raimond, S. Haroche

Published Jun 26, 1978• 48 citations
Publisher

Abstract

We report observation of modulations in superradiance, resulting from the beating of light fields emitted by two groups of atoms with different velocities. The beat note is displayed from atomic frequency by the Doppler shift corresponding to the velocity difference (red or blue shift, depending on the direction of superradiant emission). Similarly many-atom beats should occur in superradiance from a mixture of different isotopes. Implications in spectroscopy are considered.

DOI
10.1103/physrevlett.40.1711

Related papers

Observation of superradiance in Rb vapour

J Marek

Using laser excitation of the 6 2 P levels in the natural isotopic mixture of Rb atoms, modulation of superradiance intensity from some transitions to the lower levels was observed. On the transition 6 2 P 1/2 -6 2 S 1/2 this effect is interpreted as a quantum beat between the hyperfine-structure transitions of the Rb 85 and Rb 87 isotopes. A nearly 'single-pulse' superradiant signal was obtained on the 6 2 P-4 2 D transitions. When a magnetic field was applied transverse to the direction of the laser beam, the pulses obtained showed the properties forecast by two-level superradiance theory. Preliminary results are reported.

Journal of Physics B Atomic and Molecular Physics•Apr 14, 1979•40 citations

Doppler-Free Superradiance Experiments with Rb Atoms: Polarization Characteristics

A. Crubellier, Sylvain Liberman, P. Pillet

In order to check theoretical results obtained recently in the treatment of the superradiant emission of atoms when taking the level degeneracy into account explicitly, an experiment has been performed using a special "multiple beam" of Rb atoms. A careful study of the polarization characteristics of the emitted light has shown us several features which appear to be quite different in the superradiant emission and in the ordinary spontaneous one. An analysis is given for the few typical cases which have been observed and reported.

Physical Review Letters•Oct 30, 1978•55 citations

Superradiant Emission of Ultra-Bright Photon Pairs in Doppler-Broadened Atomic Ensemble

Yoon‐Seok Lee, Sang Min Lee, Heonoh Kim +1 more

With a recent rising interest of single photon superradiance due to its potential usefulness for efficient collection of single photon from an atomic ensemble, bright and narrow photon pair source is a key component in realization of quantum communication and quantum computer based on coherent interaction between light and atomic ensemble. We report the superradiant emission of ultra-bright photon pairs with a coincidence counting rate per input power of 64,600 cps/mW via spontaneous four-wave mixing in a thermal vapour cell. The photon-pair generation rate is enhanced by the contribution of two-photon coherence of almost atomic velocity groups in the Doppler-broadened ladder-type atomic system. The quadratic proportionality of the probability of detecting a heralded single photon as a function of the optical depth clarifies that the ultra-brightness results from the superradiance. In addition, a single photon superradiant beating at a high optical depth of the atomic ensemble is observed for the first time.

arXiv:1603.00728•Mar 2, 2016•0 citations

Coupled 'Ihmsitions in Superradiance

A. Crubellier, Catherine Bréchignac, Ph. Cahuzac +1 more

In the theoretical stuqy of superradiance, the atoms or molecules are generally considered as two-level systems. However in many experimental situations, this simple assumption is not valid. It is the case, for example, in all experiments exhibiting superradiant beats [1-3]. Moreover, these beats are sometimes due to a specific property of superradiance : the existence of interferences between different atoms. Other examples of multilevel superradiance are encountered each time one observes several superradiant transitions sharing a common level [3,4]. In addition, superradiance is generally observed between degenerate levels, and it has been alreaqy shown experimentally that the level-degeneracy influences the properties of the superradiant light, in particular its polarization characteristics [5].

•Jan 1, 1979•0 citations

Single-photon superradiant beating from a Doppler-broadened ladder-type atomic ensemble

Yoon‐Seok Lee, Sang Min Lee, Heonoh Kim +1 more

We report on heralded-single-photon superradiant beating in the spontaneous four-wave mixing process of Doppler-broadened ladder-type $^{87}\mathrm{Rb}$ atoms. When Doppler-broadened atoms contribute to two-photon coherence, the detection probability amplitudes of the heralded single photons are coherently superposed despite inhomogeneous broadened atomic media. Single-photon superradiant beating is observed, which constitutes evidence for the coherent superposition of two-photon amplitudes from different velocity classes in the Doppler-broadened atomic ensemble. We present a theoretical model in which the single-photon superradiant beating originates from the interference between wavelength-separated two-photon amplitudes via the reabsorption filtering effect.

Physical Review A•Dec 22, 2017•16 citations

Quantum beats in superradiance in sodium vapours

J Marek, M. Ryschka

Intensity modulations have been observed in the superradiant signals on the 4 2 P 1/2 -4 2 S 1/2 transitions obtained by pulsed dye laser beam excitation of the 4 2 P 1/2 level in Na vapour. The modulations were interpreted as beats among the frequencies of the electric dipole transitions resulting from the different HFS levels. The HFS splitting both of the upper and the lower levels must be taken into consideration in explaining the observed signals. Preliminary results of the study are reported, in particular the characteristics of the time development and polarisation of the superradiance.

Journal of Physics B Atomic and Molecular Physics•Aug 28, 1980•4 citations
We report observation of modulations in superradiance, resulting from the beating of light fields emitted by two groups of atoms with different velocities. The beat note is displayed from atomic frequency by the Doppler shift corresponding to the velocity difference (red or blue shift, depending on the direction of superradiant emission). Similarly many-atom beats should occur in superradiance from a mixture of different isotopes. Implications in spectroscopy are considered.
Using laser excitation of the 6 2 P levels in the natural isotopic mixture of Rb atoms, modulation of superradiance intensity from some transitions to the lower levels was observed. On the transition 6 2 P 1/2 -6 2 S 1/2 this effect is interpreted as a quantum beat between the hyperfine-structure transitions of the Rb 85 and Rb 87 isotopes. A nearly 'single-pulse' superradiant signal was obtained on the 6 2 P-4 2 D transitions. When a magnetic field was applied transverse to the direction of the laser beam, the pulses obtained showed the properties forecast by two-level superradiance theory. Preliminary results are reported.
In order to check theoretical results obtained recently in the treatment of the superradiant emission of atoms when taking the level degeneracy into account explicitly, an experiment has been performed using a special "multiple beam" of Rb atoms. A careful study of the polarization characteristics of the emitted light has shown us several features which appear to be quite different in the superradiant emission and in the ordinary spontaneous one. An analysis is given for the few typical cases which have been observed and reported.
With a recent rising interest of single photon superradiance due to its potential usefulness for efficient collection of single photon from an atomic ensemble, bright and narrow photon pair source is a key component in realization of quantum communication and quantum computer based on coherent interaction between light and atomic ensemble. We report the superradiant emission of ultra-bright photon pairs with a coincidence counting rate per input power of 64,600 cps/mW via spontaneous four-wave mixing in a thermal vapour cell. The photon-pair generation rate is enhanced by the contribution of two-photon coherence of almost atomic velocity groups in the Doppler-broadened ladder-type atomic system. The quadratic proportionality of the probability of detecting a heralded single photon as a function of the optical depth clarifies that the ultra-brightness results from the superradiance. In addition, a single photon superradiant beating at a high optical depth of the atomic ensemble is observed for the first time.
In the theoretical stuqy of superradiance, the atoms or molecules are generally considered as two-level systems. However in many experimental situations, this simple assumption is not valid. It is the case, for example, in all experiments exhibiting superradiant beats [1-3]. Moreover, these beats are sometimes due to a specific property of superradiance : the existence of interferences between different atoms. Other examples of multilevel superradiance are encountered each time one observes several superradiant transitions sharing a common level [3,4]. In addition, superradiance is generally observed between degenerate levels, and it has been alreaqy shown experimentally that the level-degeneracy influences the properties of the superradiant light, in particular its polarization characteristics [5].
We report on heralded-single-photon superradiant beating in the spontaneous four-wave mixing process of Doppler-broadened ladder-type 87Rb^{87}\mathrm{Rb}87Rb atoms. When Doppler-broadened atoms contribute to two-photon coherence, the detection probability amplitudes of the heralded single photons are coherently superposed despite inhomogeneous broadened atomic media. Single-photon superradiant beating is observed, which constitutes evidence for the coherent superposition of two-photon amplitudes from different velocity classes in the Doppler-broadened atomic ensemble. We present a theoretical model in which the single-photon superradiant beating originates from the interference between wavelength-separated two-photon amplitudes via the reabsorption filtering effect.
Intensity modulations have been observed in the superradiant signals on the 4 2 P 1/2 -4 2 S 1/2 transitions obtained by pulsed dye laser beam excitation of the 4 2 P 1/2 level in Na vapour. The modulations were interpreted as beats among the frequencies of the electric dipole transitions resulting from the different HFS levels. The HFS splitting both of the upper and the lower levels must be taken into consideration in explaining the observed signals. Preliminary results of the study are reported, in particular the characteristics of the time development and polarisation of the superradiance.