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

PhotoniX

Sub-shot-noise Rydberg EIT spectrum

Hongmei Yan, Mingyong Jing, Yanjie Tong, Wenguang Yang, Hao Zhang, Zong-Kai Liu, Junyao Xie, Yaohui Zheng, Liantuan Xiao, Suotang Jia, Linjie Zhang

Published Dec 15, 2025• 5 citations
Publisher

Abstract

Abstract Atom-based sensing with optical readout is fundamentally limited by photon shot noise. Squeezed light can effectively suppress this noise of optical readout, thereby enabling measurement sensitivities beyond the standard quantum limit, but their application in light–atom hybrid systems is often hindered by absorption losses of atomic medium. Here, we demonstrate the first realization of electromagnetically induced transparency spectrum in a Rydberg-atom system using a squeezed probe field that surpasses the photon shot noise limit. Our theoretical model identifies atomic transit and absorption-induced losses as the primary factors limiting squeezing preservation. Experimentally, we engineer the atomic ensemble as a medium with tunable transmittance by employing Doppler-matched velocity-selective excitation to suppress absorption, achieving a squeezing transmission of 90.4 $$\%$$ % for -1.7 dB squeezed light through a cesium vapor cell. This work is a critical step towards quantum-enhanced Rydberg atom sensors.

DOI
10.1186/s43074-025-00215-1

Related papers

Quantum Advantage with Seeded Squeezed Light for Absorption Measurement

Fu Li, Tian Li, Marlan O. Scully +1 more

Absorption measurement is an exceptionally versatile tool for many applications in science and engineering. For absorption measurements using laser beams of light, the sensitivity is theoretically limited by the shot noise due to the fundamental Poisson distribution of the photon number in laser radiation. In practice, the shot-noise limit can only be achieved when all other sources of noise are eliminated. Here, we use seeded squeezed light to demonstrate that direct-absorption measurements can be performed with a sensitivity beyond the shot-noise limit. We present a practically realizable scheme, where intensity-squeezed beams are generated by a seeded four-wave mixing process in an atomic rubidium-vapor cell. More than 1.2 dB quantum advantage for the measurement sensitivity is obtained at faint absorption levels ($\ensuremath{\le}10\mathrm{%}$). We also present a detailed theoretical analysis to show that the observed quantum advantage when corrected for optical loss would be equivalent to 3 dB. Our experiment demonstrates a direct sub-shot-noise measurement of absorption that requires neither homodyne or lock-in nor logic coincidence-detection schemes. It is therefore very applicable in many circumstances where sub-shot-noise-level absorption measurements are highly desirable.

arXiv:2007.05583•Physical Review Applied•Apr 20, 2021•33 citations

Noise spectroscopy in Rydberg atomic ensemble

Jun He, Qiang Liu, Ze Yang +4 more

The phase noise of incident light fields can be converted into amplitude noise via absorption and dispersion effects in media under electromagnetically induced transparency. The conversion process is sensitive to two-photon detuning. This effect can be used to perform a novel type of Rydberg spectroscopy. We present experimental measurements of the phase noise spectrum (PNS) with Rydberg atoms in a cesium vapor cell. Furthermore, to explore microwave field measurements, a modulation-enhanced PNS approach is proposed.

arXiv:2111.10019•Nov 19, 2021•0 citations

Photon shot-noise-limited Rydberg-EIT electrometry

Gyeongmin Ju, Ye Jin Yu, Heewoo Kim +4 more

Rydberg-atom electrometry is a core technique in the development of highly sensitive quantum electric-field sensors. Its sensitivity based on atom-photon interaction is typically limited by photon shot-noise (PSN) and spectral broadenings. Here, we experimentally demonstrate a near PSN-limited Rydberg electrometry from a 85Rb atomic vapor cell. By engineering atomic coherence through control of residual magnetic fields and laser frequency noise, we achieve the Rydberg electromagnetically induced transparency (EIT) with the narrow linewidth of 1.6 MHz, yielding an enhanced spectral slope for high-sensitivity Rydberg-EIT electrometry. Under optimized superheterodyne detection conditions, we obtain an electric-field sensitivity of 12.5(8) nV cm^-1 Hz^-1/2 at 37 GHz, in close agreement with the calculated PSN limit. These results provide direct experimental evidence of the high-sensitive quantum electrometry and establish a practical route toward quantum-noise-limited Rydberg electrometry.

physics.atom-phCross-listedarXiv:2606.04354•Jun 4, 2026•0 citations

Quantum-enhanced electrometer based on microwave-dressed Rydberg atoms

Shuhe Wu, Dong Zhang, Zheng-Chun Li +6 more

Rydberg atoms have shown remarkable performance in sensing microwave fields. The sensitivity of such an electrometer based on optical readout of the atomic ensemble has been demonstrated to approach the photon-shot-noise limit. However, the sensitivity cannot be promoted infinitely by increasing the power of the probe light due to the increased collision rates and power broadening. Compared with classical light, the use of quantum light may lead to a better sensitivity with a lower number of photons. In this paper, we exploit entanglement in a microwave-dressed Rydberg electrometer to suppress the fluctuation of noise. The results show a sensitivity enhancement that beats the shot-noise limit in both cold- and hot-atom schemes. Through optimizing the transmission of the optical readout, our quantum advantage can be maintained with differing absorptive indexes of the atomic vapor, which makes it possible to apply a quantum light source in the absorptive electrometer.

arXiv:2307.05183•Physical Review Applied•Dec 15, 2023•13 citations

Quantum-enhanced Electrometer Based on Microwave-dressed Rydberg Atoms

Dong Zhang, Shuhe Wu, Guzhi Bao +1 more

Rydberg atoms have been shown remarkable performance in sensing microwave field. The sensitivity of such an electrometer based on optical readout of atomic ensemble has been demonstrated to approach the photon-shot-noise limit. However, the sensitivity can not be promoted infinitely by increasing the power of probe light due to the increased collision rates and power broadening. Compared with classical light, the use of quantum light may lead to a better sensitivity with lower number of photons. In this paper, we exploit entanglement in a microwave-dressed Rydberg electrometer to suppress the fluctuation of noise. The results show a sensitivity enhancement beating the shot noise limit in both cold and hot atom schemes. Through optimizing the transmission of optical readout, our quantum advantage can be maintained with different absorptive index of atomic vapor, which makes it possible to apply quantum light source in the absorptive electrometer.

Photonics & Electromagnetics Research Symposium (PIERS)•Apr 21, 2024•0 citations

Noise spectroscopy with a Rydberg ensemble in a hot atomic vapor cell

Jun He, Qiang Liu, Ze Yang +3 more

The phase noise of incident light fields can be converted into amplitude noise via absorption and dispersion effects in media under electromagnetically induced transparency. The conversion process is sensitive to two-photon detuning. This effect can be used to perform a different type of Rydberg spectroscopy. We present experimental measurements of the phase noise spectrum (PNS) with Rydberg atoms in a cesium vapor cell. Furthermore, to explore microwave field measurements, a modulation-enhanced PNS approach has been proposed and demonstrated.

Physical Review A•Dec 27, 2021•17 citations
Abstract Atom-based sensing with optical readout is fundamentally limited by photon shot noise. Squeezed light can effectively suppress this noise of optical readout, thereby enabling measurement sensitivities beyond the standard quantum limit, but their application in light–atom hybrid systems is often hindered by absorption losses of atomic medium. Here, we demonstrate the first realization of electromagnetically induced transparency spectrum in a Rydberg-atom system using a squeezed probe field that surpasses the photon shot noise limit. Our theoretical model identifies atomic transit and absorption-induced losses as the primary factors limiting squeezing preservation. Experimentally, we engineer the atomic ensemble as a medium with tunable transmittance by employing Doppler-matched velocity-selective excitation to suppress absorption, achieving a squeezing transmission of 90.4 %\%% % for -1.7 dB squeezed light through a cesium vapor cell. This work is a critical step towards quantum-enhanced Rydberg atom sensors.
Absorption measurement is an exceptionally versatile tool for many applications in science and engineering. For absorption measurements using laser beams of light, the sensitivity is theoretically limited by the shot noise due to the fundamental Poisson distribution of the photon number in laser radiation. In practice, the shot-noise limit can only be achieved when all other sources of noise are eliminated. Here, we use seeded squeezed light to demonstrate that direct-absorption measurements can be performed with a sensitivity beyond the shot-noise limit. We present a practically realizable scheme, where intensity-squeezed beams are generated by a seeded four-wave mixing process in an atomic rubidium-vapor cell. More than 1.2 dB quantum advantage for the measurement sensitivity is obtained at faint absorption levels ($\ensuremath{\le}10\mathrm{%}$). We also present a detailed theoretical analysis to show that the observed quantum advantage when corrected for optical loss would be equivalent to 3 dB. Our experiment demonstrates a direct sub-shot-noise measurement of absorption that requires neither homodyne or lock-in nor logic coincidence-detection schemes. It is therefore very applicable in many circumstances where sub-shot-noise-level absorption measurements are highly desirable.
The phase noise of incident light fields can be converted into amplitude noise via absorption and dispersion effects in media under electromagnetically induced transparency. The conversion process is sensitive to two-photon detuning. This effect can be used to perform a novel type of Rydberg spectroscopy. We present experimental measurements of the phase noise spectrum (PNS) with Rydberg atoms in a cesium vapor cell. Furthermore, to explore microwave field measurements, a modulation-enhanced PNS approach is proposed.
Rydberg-atom electrometry is a core technique in the development of highly sensitive quantum electric-field sensors. Its sensitivity based on atom-photon interaction is typically limited by photon shot-noise (PSN) and spectral broadenings. Here, we experimentally demonstrate a near PSN-limited Rydberg electrometry from a 85Rb atomic vapor cell. By engineering atomic coherence through control of residual magnetic fields and laser frequency noise, we achieve the Rydberg electromagnetically induced transparency (EIT) with the narrow linewidth of 1.6 MHz, yielding an enhanced spectral slope for high-sensitivity Rydberg-EIT electrometry. Under optimized superheterodyne detection conditions, we obtain an electric-field sensitivity of 12.5(8) nV cm^-1 Hz^-1/2 at 37 GHz, in close agreement with the calculated PSN limit. These results provide direct experimental evidence of the high-sensitive quantum electrometry and establish a practical route toward quantum-noise-limited Rydberg electrometry.
Rydberg atoms have shown remarkable performance in sensing microwave fields. The sensitivity of such an electrometer based on optical readout of the atomic ensemble has been demonstrated to approach the photon-shot-noise limit. However, the sensitivity cannot be promoted infinitely by increasing the power of the probe light due to the increased collision rates and power broadening. Compared with classical light, the use of quantum light may lead to a better sensitivity with a lower number of photons. In this paper, we exploit entanglement in a microwave-dressed Rydberg electrometer to suppress the fluctuation of noise. The results show a sensitivity enhancement that beats the shot-noise limit in both cold- and hot-atom schemes. Through optimizing the transmission of the optical readout, our quantum advantage can be maintained with differing absorptive indexes of the atomic vapor, which makes it possible to apply a quantum light source in the absorptive electrometer.
Rydberg atoms have been shown remarkable performance in sensing microwave field. The sensitivity of such an electrometer based on optical readout of atomic ensemble has been demonstrated to approach the photon-shot-noise limit. However, the sensitivity can not be promoted infinitely by increasing the power of probe light due to the increased collision rates and power broadening. Compared with classical light, the use of quantum light may lead to a better sensitivity with lower number of photons. In this paper, we exploit entanglement in a microwave-dressed Rydberg electrometer to suppress the fluctuation of noise. The results show a sensitivity enhancement beating the shot noise limit in both cold and hot atom schemes. Through optimizing the transmission of optical readout, our quantum advantage can be maintained with different absorptive index of atomic vapor, which makes it possible to apply quantum light source in the absorptive electrometer.
The phase noise of incident light fields can be converted into amplitude noise via absorption and dispersion effects in media under electromagnetically induced transparency. The conversion process is sensitive to two-photon detuning. This effect can be used to perform a different type of Rydberg spectroscopy. We present experimental measurements of the phase noise spectrum (PNS) with Rydberg atoms in a cesium vapor cell. Furthermore, to explore microwave field measurements, a modulation-enhanced PNS approach has been proposed and demonstrated.