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:1308.0849 · Physical Review A

Power-broadening-free correlation spectroscopy in cold atoms

H. M. Florez, Luciano Soares da Cruz, Marcio H. G. de Miranda, Rafael Alves De Oliveira, J. W. R. Tabosa, M. Martinelli, D. Felinto

Published Sep 5, 2013• 18 citations
arXivHTMLPDF

Abstract

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.

DOI
10.1103/physreva.88.033812

Related papers

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

Noise spectroscopy in cold Rubidium atoms in EIT configuration

Klara Theophilo

Using noise spectroscopy, we studied the correlations between two light beams with opposite circular polarization, coupling the transition F=2 -> F’=2 in Λ EIT configuration, with cold atoms of Rubidium-85. In the spectrum of correlation we observed the transition from correlation to anti-correlation, off-resonance, when raising the potency of the beams.This transition is a consequence of the competition between four-wave mixing, which is responsible for the correlation regime, and the Stark effect that produces anti-correlation in the beams.In the spectra of mean signal of intensity and correlation, we observed that the EIT peak is free of potency broadening, which makes possible that the measure of coherence time be more precise in the condition of EIT. Using a EIT’s model for a system in Λ configuration, we observed that the theoretical correlation spectra are in good accordance with the experimental data, considering the degenerescence of the hyperfine levels. Besides that, the model predicts the non-broadening of the correlation peak, showing the correlation as a characterization property more accurated than the mean signal of intensity.

Physicae Proceedings•Mar 29, 2012•0 citations

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 spectra and correlations of intensity fluctuations in electromagnetically induced transparency

Vladimir A. Sautenkov, Hebin Li, Yuri V. Rostovtsev +1 more

The quantum fluctuations of optical beams are highly correlated in electromagnetically induced transparency (EIT). The intensity fluctuations are enhanced by conversion of phase noise to intensity noise in atomic vapour. We have studied spectra of intensity fluctuations in dense rubidium vapour for different laser beam powers. Observed excess noise spectrum is broader than EIT window at the same optical power. Both spectral widths are proportional to the laser beam intensity. By using signal subtraction scheme we can reduce amplitude of the fluctuations to close the photonic short noise level. This result confirms the high degrees of intensity correlations and can be used to improve quality of optical atomic clocks.

Journal of Modern Optics•Nov 10, 2007•12 citations

Electromagnetically induced transparency with noisy lasers

Yanhong Xiao, Tun Wang, Masha Baryakhtar +8 more

We demonstrate and characterize two coherent phenomena that can mitigate the effects of laser phase noise for electromagnetically induced transparency (EIT): a laser-power-broadening-resistant resonance in the transmitted intensity cross correlation between EIT optical fields, and a resonant suppression of the conversion of laser phase noise to intensity noise when one-photon noise dominates over two-photon-detuning noise. Our experimental observations are in good agreement with both an intuitive physical picture and numerical calculations. The results have wide-ranging applications to spectroscopy, atomic clocks, and magnetometers.

Physical Review A•Oct 9, 2009•38 citations

Transition linewidth of cross correlations in random intensity fluctuations in electromagnetically induced transparency

Lei Feng, Pengxiong Li, Mengzhen Zhang +2 more

It is known that cross correlation between the random intensity fluctuations of two lasers forming electromagnetically induced transparency (EIT) exhibits a transition from correlation to anticorrelation. We study the linewidth behavior of this transition and have found the linewidth is below the (effective) coherence lifetime limit and is limited only by competing noises. We established a numerical model which reveals the linewidth dependence on laser linewidth and laser power. Our experiments using lasers with different linewidth showed results in qualitative agreement with the model. This result is useful for quantum optics using EIT and may also have applications in spectroscopy and precision measurements.

Physical Review A•Jan 14, 2014•7 citations
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 \ensuremathΛ\ensuremath{\Lambda}\ensuremathΛ 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.
Using noise spectroscopy, we studied the correlations between two light beams with opposite circular polarization, coupling the transition F=2 -> F’=2 in Λ EIT configuration, with cold atoms of Rubidium-85. In the spectrum of correlation we observed the transition from correlation to anti-correlation, off-resonance, when raising the potency of the beams.This transition is a consequence of the competition between four-wave mixing, which is responsible for the correlation regime, and the Stark effect that produces anti-correlation in the beams.In the spectra of mean signal of intensity and correlation, we observed that the EIT peak is free of potency broadening, which makes possible that the measure of coherence time be more precise in the condition of EIT. Using a EIT’s model for a system in Λ configuration, we observed that the theoretical correlation spectra are in good accordance with the experimental data, considering the degenerescence of the hyperfine levels. Besides that, the model predicts the non-broadening of the correlation peak, showing the correlation as a characterization property more accurated than the mean signal of intensity.
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.
The quantum fluctuations of optical beams are highly correlated in electromagnetically induced transparency (EIT). The intensity fluctuations are enhanced by conversion of phase noise to intensity noise in atomic vapour. We have studied spectra of intensity fluctuations in dense rubidium vapour for different laser beam powers. Observed excess noise spectrum is broader than EIT window at the same optical power. Both spectral widths are proportional to the laser beam intensity. By using signal subtraction scheme we can reduce amplitude of the fluctuations to close the photonic short noise level. This result confirms the high degrees of intensity correlations and can be used to improve quality of optical atomic clocks.
We demonstrate and characterize two coherent phenomena that can mitigate the effects of laser phase noise for electromagnetically induced transparency (EIT): a laser-power-broadening-resistant resonance in the transmitted intensity cross correlation between EIT optical fields, and a resonant suppression of the conversion of laser phase noise to intensity noise when one-photon noise dominates over two-photon-detuning noise. Our experimental observations are in good agreement with both an intuitive physical picture and numerical calculations. The results have wide-ranging applications to spectroscopy, atomic clocks, and magnetometers.
It is known that cross correlation between the random intensity fluctuations of two lasers forming electromagnetically induced transparency (EIT) exhibits a transition from correlation to anticorrelation. We study the linewidth behavior of this transition and have found the linewidth is below the (effective) coherence lifetime limit and is limited only by competing noises. We established a numerical model which reveals the linewidth dependence on laser linewidth and laser power. Our experiments using lasers with different linewidth showed results in qualitative agreement with the model. This result is useful for quantum optics using EIT and may also have applications in spectroscopy and precision measurements.