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

arXiv:1508.04858 · Physical Review A

Correlation spectroscopy in cold atoms: Light sideband resonances in electromagnetically-induced-transparency condition

H. M. Florez, Ashok Kumar, Klara Theophilo, P. Nussenzveig, M. Martinelli

Published Jul 6, 2016• 2 citations
arXivHTMLPDF

Abstract

The correlation spectroscopy has been successfully employed in the measurement of the intrinsic linewidth of electromagnetically induced transparency (EIT) in time and frequency domain. We study the role of the sidebands of the intense fields in the measured spectra, analyzing the information that can be recovered working with different analysis frequencies. In this case, the nonzero one-photon detuning appears as a necessary condition for spectrally resolving the sideband resonances in the correlation coefficient. Our experimental findings are supported by the perturbative model defined in the frequency domain.

DOI
10.1103/physreva.94.012504

Related papers

Perturbative approach in the frequency domain for the intensity correlation spectrum in electromagnetically induced transparency

H. M. Florez, C. González, M. Martinelli

Correlation spectroscopy has been proposed as a spectroscopic technique for measuring the coherence between the ground states in electromagnetically induced transparency (EIT). While in the time domain the steep dispersion in the EIT condition accounts for the robustness of the correlation linewidth against power broadening, such physical insight was not directly established in the frequency domain. We propose a perturbative approach to describe the correlation spectroscopy of two noisy lasers coupled to a $\mathrm{\ensuremath{\Lambda}}$ transition in cold atoms, leading to EIT. Such approach leads to an analytical expression that maps the intensity correlation directly in terms of the absorption and dispersion of the light fields. Low and high perturbative regimes are investigated and demonstrate that, for coherent light sources, the first-order term in perturbation expansion represents a sufficient description for the correlation. Sideband resonances are also observed, showing the richness of the frequency domain approach.

arXiv:1603.09312•Physical Review A•Jul 6, 2016•4 citations

Power-broadening-free correlation spectroscopy in cold atoms

H. M. Florez, Luciano Soares da Cruz, Marcio H. G. de Miranda +4 more

We report a detailed investigation on the properties of intensity correlation spectra for laser beams interacting with cold atoms under the condition of electromagnetically induced transparency (EIT). We describe the transition of their intensity fluctuations from correlation to anticorrelation as the mean intensity of the fields increases. Such a transition occurs for laser frequencies around the EIT resonance, which is characterized by a correlation peak. The transition point between correlation and anticorrelation is independent of power broadening and provides directly the ground-state coherence time. We introduce a method to extract in real time the correlation spectra of the system. The experiments were done in two distinct magneto-optical traps, one for cesium and the other for rubidium atoms, employing different detection schemes. A simplified theory is introduced assuming three-level atoms in $\ensuremath{\Lambda}$ configuration interacting with a laser with stochastic phase fluctuations, providing a good agreement with the experimental observations.

arXiv:1308.0849•Physical Review A•Sep 5, 2013•18 citations

Physical interpretation for the correlation spectra of electromagnetically-induced-transparency resonances

D. Felinto, Luciano Soares da Cruz, Rafael Alves De Oliveira +5 more

The phenomenon called Electromagnetically Induced Transparency (EIT) may induce different types of correlation between two optical fields interacting with an ensemble of atoms. It is presently well known, for example, that in the vicinity of an EIT resonance the dominant correlations at low powers turn into anti-correlations as power increases. Such correlation spectra present striking power-broadening-independent features, with the best condition for measuring the characteristic linewidth occurring at the highest powers. In the present work we investigate the physical mechanisms responsible for this set of observations. Our approach is first to reproduce these effects in a better controlled experimental setup: a cold atomic ensemble, obtained from a magneto-optical trap. The results from this conceptually simpler system were then compared to a correspondingly simpler theory, which clearly relates the observed features to the interplay between two key aspects of EIT: the transparency itself and the steep normal dispersion near two-photon resonance.

Optics Express•Jan 14, 2013•14 citations

Resolving multiple peaks using a sub-transit-linewidth cross-correlation resonance

Pengxiong Li, Lei Feng, Yanhong Xiao

In a recent paper [L. Feng et al., Phys. Rev. Lett. 109, 233006 (2012)], we demonstrated a sub-transit-linewidth resonance based on cross correlation between optical fields in an electromagnetically induced transparency (EIT) system. Here, we investigate the ability of such resonance to resolve multiple resonance peaks. We first report the implementation of the cross-correlation resonance in a hyperfine EIT system, with a linewidth of about $1/16$ of the transit EIT width. Then, a magnetic field is applied to create multipeak EIT resonance with tunable spacing. Cross-correlation resonance with multipeaks is observed and the line shape agrees qualitatively with our numerical simulations. We find that the multipeak correlation resonance has better contrast than the corresponding EIT resonance, but with a lower signal to noise. Furthermore, this correlation resonance cannot resolve peaks with spacing close to or less than the intrinsic width, like any other resonance techniques. We analyze the origin of this limitation and make connections to the Ramsey-type subnatural spectroscopy technique. This work shows potential applications of the correlation resonance in atomic frequency standard and laser spectroscopy.

Physical Review A•Apr 22, 2014•3 citations

Probing light forces on cold atoms by noise correlation spectroscopy

Klara Theophilo, Ashok Kumar, H. M. Florez +3 more

Enhanced sensitivity in electromagnetically induced transparency (EIT) can be obtained by the use of noise correlation spectroscopy between the fields involved in the process. Here, we investigate EIT in a cold ($<1$ mK) rubidium vapor and demonstrate sensitivity to detect weak light-induced forces on the atoms. A theoretical model is developed and shows good agreement with our measurements, enabling the attribution of the observed effects to the coupling of the atomic states to their motion. The effects remain unnoticed on the measurement of the mean fields but are clearly manifest in their correlations.

arXiv:1808.02918•Physical Review A•Nov 19, 2018•3 citations

Nonlinear optical spectra from Rydberg-mediated photon-photon interactions

Xinghan Wang, Yupeng Wang, Aishik Panja +1 more

While Rydberg-Rydberg interactions are essential for quantum nonlinear optics and quantum information processing, their role in microwave and radio-frequency sensing remains poorly understood. Here we experimentally investigate Rydberg interaction-induced nonlinearity in cold-atom Rydberg electromagnetically induced transparency (EIT). In a three-level EIT system, increasing photon-photon interactions produces nonlinear spectral broadening accompanied by resonance shifts, while a microwave-dressed four-level system exhibits pronounced nonlinear broadening without detectable spectral shifts. Our three-level data can be explained by a conditional superatom model, whereas our four-level observations are surprisingly captured by a simple dephasing model. Comparisons with three representative models provide key insights to the role of many-body interactions in Rydberg EIT spectroscopy. Furthermore, our results clarify the conditions under which microwave field characterization can be performed in the nonlinear regime without introducing systematic bias. Our study advances both fundamental understanding of many-body physics and practical development of atomic sensors.

arXiv:2602.11563•Feb 12, 2026•0 citations
The correlation spectroscopy has been successfully employed in the measurement of the intrinsic linewidth of electromagnetically induced transparency (EIT) in time and frequency domain. We study the role of the sidebands of the intense fields in the measured spectra, analyzing the information that can be recovered working with different analysis frequencies. In this case, the nonzero one-photon detuning appears as a necessary condition for spectrally resolving the sideband resonances in the correlation coefficient. Our experimental findings are supported by the perturbative model defined in the frequency domain.
Correlation spectroscopy has been proposed as a spectroscopic technique for measuring the coherence between the ground states in electromagnetically induced transparency (EIT). While in the time domain the steep dispersion in the EIT condition accounts for the robustness of the correlation linewidth against power broadening, such physical insight was not directly established in the frequency domain. We propose a perturbative approach to describe the correlation spectroscopy of two noisy lasers coupled to a $\mathrm{\ensuremath{\Lambda}}$ transition in cold atoms, leading to EIT. Such approach leads to an analytical expression that maps the intensity correlation directly in terms of the absorption and dispersion of the light fields. Low and high perturbative regimes are investigated and demonstrate that, for coherent light sources, the first-order term in perturbation expansion represents a sufficient description for the correlation. Sideband resonances are also observed, showing the richness of the frequency domain approach.
We report a detailed investigation on the properties of intensity correlation spectra for laser beams interacting with cold atoms under the condition of electromagnetically induced transparency (EIT). We describe the transition of their intensity fluctuations from correlation to anticorrelation as the mean intensity of the fields increases. Such a transition occurs for laser frequencies around the EIT resonance, which is characterized by a correlation peak. The transition point between correlation and anticorrelation is independent of power broadening and provides directly the ground-state coherence time. We introduce a method to extract in real time the correlation spectra of the system. The experiments were done in two distinct magneto-optical traps, one for cesium and the other for rubidium atoms, employing different detection schemes. A simplified theory is introduced assuming three-level atoms in $\ensuremath{\Lambda}$ configuration interacting with a laser with stochastic phase fluctuations, providing a good agreement with the experimental observations.
The phenomenon called Electromagnetically Induced Transparency (EIT) may induce different types of correlation between two optical fields interacting with an ensemble of atoms. It is presently well known, for example, that in the vicinity of an EIT resonance the dominant correlations at low powers turn into anti-correlations as power increases. Such correlation spectra present striking power-broadening-independent features, with the best condition for measuring the characteristic linewidth occurring at the highest powers. In the present work we investigate the physical mechanisms responsible for this set of observations. Our approach is first to reproduce these effects in a better controlled experimental setup: a cold atomic ensemble, obtained from a magneto-optical trap. The results from this conceptually simpler system were then compared to a correspondingly simpler theory, which clearly relates the observed features to the interplay between two key aspects of EIT: the transparency itself and the steep normal dispersion near two-photon resonance.
In a recent paper [L. Feng et al., Phys. Rev. Lett. 109, 233006 (2012)], we demonstrated a sub-transit-linewidth resonance based on cross correlation between optical fields in an electromagnetically induced transparency (EIT) system. Here, we investigate the ability of such resonance to resolve multiple resonance peaks. We first report the implementation of the cross-correlation resonance in a hyperfine EIT system, with a linewidth of about 1/161/161/16 of the transit EIT width. Then, a magnetic field is applied to create multipeak EIT resonance with tunable spacing. Cross-correlation resonance with multipeaks is observed and the line shape agrees qualitatively with our numerical simulations. We find that the multipeak correlation resonance has better contrast than the corresponding EIT resonance, but with a lower signal to noise. Furthermore, this correlation resonance cannot resolve peaks with spacing close to or less than the intrinsic width, like any other resonance techniques. We analyze the origin of this limitation and make connections to the Ramsey-type subnatural spectroscopy technique. This work shows potential applications of the correlation resonance in atomic frequency standard and laser spectroscopy.
Enhanced sensitivity in electromagnetically induced transparency (EIT) can be obtained by the use of noise correlation spectroscopy between the fields involved in the process. Here, we investigate EIT in a cold (<1<1<1 mK) rubidium vapor and demonstrate sensitivity to detect weak light-induced forces on the atoms. A theoretical model is developed and shows good agreement with our measurements, enabling the attribution of the observed effects to the coupling of the atomic states to their motion. The effects remain unnoticed on the measurement of the mean fields but are clearly manifest in their correlations.
While Rydberg-Rydberg interactions are essential for quantum nonlinear optics and quantum information processing, their role in microwave and radio-frequency sensing remains poorly understood. Here we experimentally investigate Rydberg interaction-induced nonlinearity in cold-atom Rydberg electromagnetically induced transparency (EIT). In a three-level EIT system, increasing photon-photon interactions produces nonlinear spectral broadening accompanied by resonance shifts, while a microwave-dressed four-level system exhibits pronounced nonlinear broadening without detectable spectral shifts. Our three-level data can be explained by a conditional superatom model, whereas our four-level observations are surprisingly captured by a simple dephasing model. Comparisons with three representative models provide key insights to the role of many-body interactions in Rydberg EIT spectroscopy. Furthermore, our results clarify the conditions under which microwave field characterization can be performed in the nonlinear regime without introducing systematic bias. Our study advances both fundamental understanding of many-body physics and practical development of atomic sensors.