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 Express

Numerical study of superradiant mixing by an unsynchronized superradiant state of multiple atomic ensembles

Haechan An, Yoonchan Jeong

Published Jun 22, 2020• 0 citations
Publisher

Abstract

We numerically analyze superradiant dynamics in atomic ensembles that have different transition frequencies using a numerical model that can take account of the transient behavior of an unsynchronized superradiant state. The numerical results unveil that the superradiant emission of a periodic pulse train can be induced by means of collective multiple frequency generation, which we call superradiant mixing. This is, in fact, due to the superradiant coupling of unsynchronized atomic ensembles. We numerically investigate the superradiant mixing in detail, varying the collective decay rate, repumping rate, and the number of the individual atomic ensembles with detuned frequencies. This work broadens our understanding of the collective atomic behavior in a detuned system, and it also suggests a novel method for frequency generation without relying on the conventional Kerr nonlinear effect.

DOI
10.1364/oe.393311

Related papers

Bifurcations and chaos in pulse-train superradiance

Albert T. Rosenberger

The superradiant response of a collection of three-level atoms to a train of pump pulses has been investigated numerically. It is assumed that the size of the system is small enough that propagation may be neglected and that the pump is resonant. The atoms are considered to be homogeneously broadened, and all relaxation rates are taken to be equal. The period of the pump pulse train is of the order of the atomic relaxation time, and the width of individual pulses is <4% of the period. Coherence remaining from previous pulses results in qualitative changes in the superradiant pulse train as the pump intensity is increased. Three cases of increasing complexity have been studied: square pump pulses, nondegenerate energy levels; mode-locked pulses, non-degenerate levels; and mode-locked pulses, degenerate levels. The sequence of behavior patterns is somewhat different for different cases. Features of the superradiant output common to the three cases are inversion of the electric field, alternation of positive and negative pulses, and recovery of pulses of one sign after more complicated behavior such as period-doubling, chaos, or intermittency. The effects of varying pump period or pulse shape are found to be less straightforward than that of varying pump intensity. The feasibility of experimental observation is discussed.

Annual Meeting Optical Society of America•Jan 1, 1988•0 citations

Collective effects and superradiance in atomic ensembles

Alexander Roth

This thesis contributes to the field of collective effects in atomic ensembles. We explore synchronization of superradiant lasers in different coupling configurations and study superradiance in off-resonantly probed atomic ensembles, where we take into account the complete level structure of alkali metal atoms. In the first part we introduce the superradiant laser and extend the discussion of synchronization of symmetrically coupled superradiant lasers to unidirectional coupled superradiant lasers. We show that synchronization is also present when we replace the superradi- ant laser couplings with classical channels, meaning the synchronization can be considered a classical effect. In the second part we generalize a widely used approximation method taking into account lower order atom-atom correlations — the cumulant expansion method — to a basis independent formalism. We implement this formalism in a Python program allowing us to numerically calculate the n-atom reduced density matrix and two-time correlation functions for ensembles of multi-level atoms. This method allows us to study the stationary state of an ensemble of off-resonantly probed alkali metal atoms with a ground-state manifold consisting of many hyperfine levels. We show that collective effects in light-matter interaction depends on the tensor-polarizability of atoms and therefore cannot be explained on the basis of two-level-approximations.

•Jan 1, 2018•4 citations

Subradiance in dilute atomic ensembles: Role of pairs and multiple scattering

Y. A. Fofanov, I. M. Sokolov, Robin Kaiser +1 more

We study numerically the slow (subradiant) decay of the fluorescence of motionless atoms after a weak pulsed excitation. We show that, in the linear-optics regime and for an excitation detuned by several natural linewidths, the slow decay rate can be dominated by close pairs of atoms (dimers) forming superradiant and subradiant states. However, for a large-enough resonant optical depth and at later time, the dynamics is dominated by collective many-body effects. In this regime, we study the polarization and the spectrum of the emitted light, as well as the spatial distribution of excitation inside the sample, as a function of time during the decay dynamics. The behavior of these observables is consistent with what would be expected for radiation trapping of nearly resonant light. This finding sheds light on subradiance in dilute samples by providing an interpretation based on the light behavior of the system (multiple scattering) which is complementary to the more commonly used picture of the collective atomic Dicke state.

arXiv:2012.10659•Physical Review A•Aug 9, 2021•16 citations

Hyperradiance from collective behavior of coherently driven atoms

Marc-Oliver Pleinert, Joachim von Zanthier, G. S. Agarwal

The collective behavior of ensembles of atoms has been studied in-depth since the seminal paper of Dicke [R. H. Dicke, Phys. Rev. 93, 99 (1954)], where he demonstrated that a group of emitters in collective states is able to radiate with increased intensity and modified decay rates in particular directions, a phenomenon which he called superradiance. Here, we show that the fundamental setup of two atoms coupled to a single-mode cavity can be distinctly exceeding the free-space superradiant behavior, a phenomenon which we call hyperradiance. The effect is accompanied by strong quantum fluctuations and surprisingly arises for atoms radiating out-of-phase, an alleged non-ideal condition, where one expects subradiance. We are able to explain the onset of hyperradiance in a transparent way by a photon cascade taking place among manifolds of Dicke states with different photon numbers under particular out-of-phase coupling conditions. The theoretical results can be realized with current technology and thus should stimulate future experiments.

arXiv:1702.05392•Optica•Jul 5, 2017•46 citations

Collective early-time spontaneous decay of a strongly driven cold atomic ensemble

Daniel Benedicto Orenes, Naudson Lucas Lopes Matias, Apoorva Apoorva +3 more

In this work we present a numerical and experimental investigation of the collective early-time decay rates of a strongly driven and optically dense cold atomic cloud. We prepare the atomic ensemble by driving the system to its steady state with varying Rabi frequencies $Ω$ that go from the weak $Ω\ll Γ$ to the strong driving regime $Ω\gg Γ$, where $Γ$ is the single-atom decay rate. We investigate the early-time dynamics in the transition between the strong and weak driving regimes using: i) angular-dependent observables such as the light emitted by the cloud, and ii) global observables, i.e., the excited state population. When driving the cloud on-resonance, we find that as a function of the driving frequency, the behavior of the collected light at certain angles transitions from the single-photon subradiant regime to a superradiant regime while the behavior of the excited state population does not show superradiance. The experiment shows good agreement with numerical predictions in the regime of parameters under study.

quant-pharXiv:2511.17187•Physical Review Research•Nov 24, 2025•0 citations

Analytical and numerical study of subradiance-only collective decay from atomic ensembles

Anirudh Yadav, Deniz D. Yavuz

We analytically and numerically study collective emission from an ensemble of atoms in the weak-excitation regime with the initial condition of uniform excitation of the ensemble. We show that under certain conditions, subradiance at the later stages of the collective decay does not necessarily need to be accompanied by early-time superradiance. We analyze the conditions where such subradiance-only decay occurs for ordered and disordered ensembles in one-, two-, and three-dimensional spatial configurations.

Physical Review A•Aug 5, 2024•2 citations
We numerically analyze superradiant dynamics in atomic ensembles that have different transition frequencies using a numerical model that can take account of the transient behavior of an unsynchronized superradiant state. The numerical results unveil that the superradiant emission of a periodic pulse train can be induced by means of collective multiple frequency generation, which we call superradiant mixing. This is, in fact, due to the superradiant coupling of unsynchronized atomic ensembles. We numerically investigate the superradiant mixing in detail, varying the collective decay rate, repumping rate, and the number of the individual atomic ensembles with detuned frequencies. This work broadens our understanding of the collective atomic behavior in a detuned system, and it also suggests a novel method for frequency generation without relying on the conventional Kerr nonlinear effect.
The superradiant response of a collection of three-level atoms to a train of pump pulses has been investigated numerically. It is assumed that the size of the system is small enough that propagation may be neglected and that the pump is resonant. The atoms are considered to be homogeneously broadened, and all relaxation rates are taken to be equal. The period of the pump pulse train is of the order of the atomic relaxation time, and the width of individual pulses is <4% of the period. Coherence remaining from previous pulses results in qualitative changes in the superradiant pulse train as the pump intensity is increased. Three cases of increasing complexity have been studied: square pump pulses, nondegenerate energy levels; mode-locked pulses, non-degenerate levels; and mode-locked pulses, degenerate levels. The sequence of behavior patterns is somewhat different for different cases. Features of the superradiant output common to the three cases are inversion of the electric field, alternation of positive and negative pulses, and recovery of pulses of one sign after more complicated behavior such as period-doubling, chaos, or intermittency. The effects of varying pump period or pulse shape are found to be less straightforward than that of varying pump intensity. The feasibility of experimental observation is discussed.
This thesis contributes to the field of collective effects in atomic ensembles. We explore synchronization of superradiant lasers in different coupling configurations and study superradiance in off-resonantly probed atomic ensembles, where we take into account the complete level structure of alkali metal atoms. In the first part we introduce the superradiant laser and extend the discussion of synchronization of symmetrically coupled superradiant lasers to unidirectional coupled superradiant lasers. We show that synchronization is also present when we replace the superradi- ant laser couplings with classical channels, meaning the synchronization can be considered a classical effect. In the second part we generalize a widely used approximation method taking into account lower order atom-atom correlations — the cumulant expansion method — to a basis independent formalism. We implement this formalism in a Python program allowing us to numerically calculate the n-atom reduced density matrix and two-time correlation functions for ensembles of multi-level atoms. This method allows us to study the stationary state of an ensemble of off-resonantly probed alkali metal atoms with a ground-state manifold consisting of many hyperfine levels. We show that collective effects in light-matter interaction depends on the tensor-polarizability of atoms and therefore cannot be explained on the basis of two-level-approximations.
We study numerically the slow (subradiant) decay of the fluorescence of motionless atoms after a weak pulsed excitation. We show that, in the linear-optics regime and for an excitation detuned by several natural linewidths, the slow decay rate can be dominated by close pairs of atoms (dimers) forming superradiant and subradiant states. However, for a large-enough resonant optical depth and at later time, the dynamics is dominated by collective many-body effects. In this regime, we study the polarization and the spectrum of the emitted light, as well as the spatial distribution of excitation inside the sample, as a function of time during the decay dynamics. The behavior of these observables is consistent with what would be expected for radiation trapping of nearly resonant light. This finding sheds light on subradiance in dilute samples by providing an interpretation based on the light behavior of the system (multiple scattering) which is complementary to the more commonly used picture of the collective atomic Dicke state.
The collective behavior of ensembles of atoms has been studied in-depth since the seminal paper of Dicke [R. H. Dicke, Phys. Rev. 93, 99 (1954)], where he demonstrated that a group of emitters in collective states is able to radiate with increased intensity and modified decay rates in particular directions, a phenomenon which he called superradiance. Here, we show that the fundamental setup of two atoms coupled to a single-mode cavity can be distinctly exceeding the free-space superradiant behavior, a phenomenon which we call hyperradiance. The effect is accompanied by strong quantum fluctuations and surprisingly arises for atoms radiating out-of-phase, an alleged non-ideal condition, where one expects subradiance. We are able to explain the onset of hyperradiance in a transparent way by a photon cascade taking place among manifolds of Dicke states with different photon numbers under particular out-of-phase coupling conditions. The theoretical results can be realized with current technology and thus should stimulate future experiments.
In this work we present a numerical and experimental investigation of the collective early-time decay rates of a strongly driven and optically dense cold atomic cloud. We prepare the atomic ensemble by driving the system to its steady state with varying Rabi frequencies ΩΩΩ that go from the weak Ω≪ΓΩ\ll ΓΩ≪Γ to the strong driving regime Ω≫ΓΩ\gg ΓΩ≫Γ, where ΓΓΓ is the single-atom decay rate. We investigate the early-time dynamics in the transition between the strong and weak driving regimes using: i) angular-dependent observables such as the light emitted by the cloud, and ii) global observables, i.e., the excited state population. When driving the cloud on-resonance, we find that as a function of the driving frequency, the behavior of the collected light at certain angles transitions from the single-photon subradiant regime to a superradiant regime while the behavior of the excited state population does not show superradiance. The experiment shows good agreement with numerical predictions in the regime of parameters under study.
We analytically and numerically study collective emission from an ensemble of atoms in the weak-excitation regime with the initial condition of uniform excitation of the ensemble. We show that under certain conditions, subradiance at the later stages of the collective decay does not necessarily need to be accompanied by early-time superradiance. We analyze the conditions where such subradiance-only decay occurs for ordered and disordered ensembles in one-, two-, and three-dimensional spatial configurations.