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 Applied

Three-photon Rydberg-atom-based radio-frequency sensing scheme with narrow linewidth

Stephanie M. Bohaichuk, Fabian Ripka, Vijin Venu, Florian Christaller, Chang Liu, Matthias Schmidt, Harald Kübler, James P. Shaffer

Published Dec 21, 2023• 41 citations
Publisher

Abstract

The self-calibration of rf sensors using Rydberg-atom vapor cells is a major advantage over conventional rf antennas, but has been limited by Doppler broadening. In this study, ultranarrow linewidths comparable to those in ultracold gases are obtained in a room-temperature vapor cell, by overcoming Doppler shifts via a three-photon scheme to reduce the spectral linewidth to less than 200 kHz. This narrow linewidth extends the self-calibrated regime of such sensors by over an order of magnitude, compared to what has been achieved in standard two-photon schemes.

DOI
10.1103/physrevapplied.20.l061004

Related papers

A Three-Photon Rydberg Atom-Based Radio Frequency Sensing Scheme with Narrow Linewidth

Stephanie M. Bohaichuk, Fabian Ripka, Vijin Venu +5 more

We demonstrate Rydberg atom-based radio frequency sensing with a colinear three-photon scheme in a room temperature cesium vapor cell that minimizes residual Doppler broadening of the probe laser absorption feature. A sub-200 kHz spectral linewidth is observed and extends the self-calibrated Autler-Townes sensing regime to weaker fields by a factor of ~18 compared to the theoretical limit of the most commonly used two-photon scheme. The sensitivity of the method to microsecond pulses is shown to be sufficient to detect radio frequency Rabi frequencies of 2$π$ x 0.44 MHz using a 480 kHz bandwidth at 108.9 GHz, demonstrating the ability to sense time-dependent signals suitable for radar and communications.

arXiv:2304.07409•Apr 14, 2023•1 citation

Three-photon Rydberg atom electrometry with enhanced sensitivity

Vijin Venu, Stephanie M. Bohaichuk, Florian Christaller +3 more

In this work, we present a high-sensitivity, all-optical, atom-based radio-frequency electrometry technique, implemented via a collinear three-photon excitation scheme in a room-temperature cesium vapor cell. By employing a wave-vector matching condition unique to cesium, our approach reduces the residual Doppler broadening so that it does not dominate the electromagnetically induced absorption linewidth, achieving linewidths below 200 kHz. The narrow linewidth enables the expansion of the self-calibrated Autler-Townes sensing regime and increased sensitivity when compared to methods where Doppler broadening dominates the linewidth. In this paper, we report our latest sensitivity measurements which successfully detected radio-frequency (RF) Rabi frequencies of 2π×43 kHz using a 480 kHz measurement bandwidth at 10.7 GHz, corresponding to a sensitivity of 45 nV/cm/ √ Hz. The results of our experiment show a thirteen-fold improvement compared to our previously reported findings for all-optical atom-based electrometry. Our measurements demonstrate the ability to detect time-varying signals suitable for radar and communication applications with high sensitivity.

Optical and Quantum Sensing and Precision Metrology II•Mar 19, 2025•0 citations

Coherent Rydberg-atom engineering for radio-frequency sensing

Matthias Schmidt

In this work, theoretical and experimental works on Rydberg-atom based radio-frequency (RF) sensors are presented. The results were obtained in close collaboration with the Quantum Valley Ideas Lab, whose goal is the miniaturization and prototyping of these sensors. The Rydberg-atom based RF sensors utilize lasers to coherently excite an atomic vapor in a vapor cell at room temperature to a highly excited Rydberg state, which is extremely sensitive to external environmental influences. In this work, Rydberg-atom based RF sensing is described as coherent multi-photon interference in the atom-light coupled system by introducing atom-light coherences. The presence of the RF wave influences the absorption of a probe laser propagating through the atomic medium. The atomic response of the Rydberg-atoms can be engineered by changing the atom-light coherences through laser power and frequency. Analytic expressions for the atomic response to the incident RF wave are derived in the weak probe limit and provide a deeper understanding of the underlying coherent multi-photon interference processes, which help to further tailor the Rydberg-atom for the purpose of the application. Good agreement with full numerical simulations of the Lindblad-master equation is found. An analysis of the various Doppler limits strongly motivates an excitation scheme where the effective wave vector mismatch on the Rydberg transition vanishes, as a promising candidate to achieve narrower spectral linewidths and, consequently, a higher sensitivity. The level structure of cesium presents a unique three-photon excitation scheme where residual Doppler shifts become comparable to the spectral linewidth of the coupling lasers. The experimental realization of this excitation scheme is demonstrated. A spectral linewidth of the Rydberg transition of 190 kHz is achieved. The measurements present the world record sensitivity, 45 nV/cm/Hz^1/2, for all-optical RF sensing with room temperature operation. These results make the three-photon excitation scheme a prime candidate for the next generation of Rydberg-atom based RF sensor prototypes. Finally, all-optical phase-sensitive RF detection is theoretically investigated in a closed-loop excitation scheme. An analytic expression is derived that intuitively describes the atomic response. Furthermore, it provides insights into the probe intensity dynamics that occur when the system is operated under finite detuning. These oscillatory dynamics allow for the extraction of the in- (I) and out- (Q) of-phase response to the RF wave, thereby enabling the simultaneous detection of the RF E-field amplitude and phase. A blueprint for the experimental realization is presented, and angle-of-arrival tolerances for the RF wave are estimated. A quadrature amplitude modulation (QAM) sequence was modelled and the simultaneous extraction of the phase and amplitude of the RF wave of interest was successfully demonstrated.

•Jan 1, 2025•0 citations

Rydberg Atom-Based Radio Frequency Electrometry: Enhancement of the Self-Calibrated Autler-Townes Sensing Mode

James P. Shaffer, Fabian Ripka, Chang Liu +6 more

We describe experiments relevant to Rydberg atom-based sensing. In Rydberg atom-based sensing, atoms contained in a vapor cell are used as a probe of an incident radio frequency electric field. We present a novel approach based on a collinear three-photon read-out and detection scheme, which extends the sensing range of the self-calibrated Autler-Townes sensing mode to lower electric field strengths. We demonstrate proof of concept and present concrete results from first experiments. We show that we are able to measure electric field strengths below 1 mV/cm in the self-calibrated Autler-Townes regime for a radial dipole moment of 2206 ea0for a transition at 10.7 GHz. We measure an Autler-Townes splitting of 503(6) kHz, which is equivalent to a radio frequency electric field strength of micro-V/cm.

IEEE Conference on Antenna Measurements & Applications•Nov 15, 2021•5 citations

Doppler sensitivity and resonant tuning of Rydberg atom-based antennas

Peter B. Weichman

Abstract Radio frequency antennas based on Rydberg atom vapor cells can in principle reach sensitivities beyond those of any conventional wire antenna, especially at lower frequencies where very long wires are needed to accommodate the increasing wavelength. They also have other desirable features such as consisting of nonmetallic, hence lower profile, elements. This paper presents a detailed theoretical investigation of Rydberg antenna sensitivity, elucidating parameter regimes that could cumulatively lead to a sensitivity increase 2–3 orders of magnitude beyond that of currently tested configurations. The key insight is to optimally combine the advantages of two well-studied approaches: (i) three laser ‘2D star configuration’ setups that, when enhanced with increased laser power, to some degree compensate for atom motion-induced Doppler broadening, and (ii) resonant coupling between a pair of near-degenerate Rydberg levels, tuned via a local oscillator to the incident signal of interest. The advantage of the star setup is subtle because it only restores the overall sensitivity to the expected Doppler-limited value, compensating for additional significant off-resonance reductions where differently moving atom sub-populations destructively interfere with each other in the net signal. An additional unique advantage of local oscillator tuning is that it leads to vastly narrower line widths, as low as ∼10 kHz set by the intrinsic Rydberg state lifetimes, rather than the typical ∼10 MHz scale set by the core state lifetimes. Intuitively, with this setup the two Rydberg states may be tuned to act as an independent high-q cavity, a point of view supported by a study of the frequency-dependence of the antenna resonant response. There are a number of practical experimental advances, especially larger ∼1 cm laser beam widths, required to suppress various extrinsic line broadening effects and to fully exploit this ‘Rydberg superheterodyne’ response.

arXiv:2405.07993•Journal of Physics B Atomic Molecular and Optical Physics•Jul 15, 2024•7 citations

Doppler-free Rydberg spectroscopy in a warm vapor

Jeremy Glick, Brielle E. Anderson, T. Nathan Nunley +4 more

The common approach for producing Rydberg atoms in warm vapor cells is with lasers arranged in a counterpropagating, collinear configuration. Doppler effects in these configurations reduce the efficiency of excitation to the Rydberg state while also producing broadened spectral features. In this work, we demonstrate a three-laser Doppler-free excitation using laser beams whose k vectors sum to 0, resulting in an enhancement in the Rydberg density and narrowed spectral features. A three-times enhancement to Rydberg density along with a near four-times reduction in spectroscopic linewidths are observed compared to a collinear configuration. This Doppler-free configuration could prove beneficial to Rydberg atomic technologies, such as electric field sensing with small volumes or deterministic photon sources.

arXiv:2506.04504•Physical Review A•Oct 2, 2025•3 citations
The self-calibration of rf sensors using Rydberg-atom vapor cells is a major advantage over conventional rf antennas, but has been limited by Doppler broadening. In this study, ultranarrow linewidths comparable to those in ultracold gases are obtained in a room-temperature vapor cell, by overcoming Doppler shifts via a three-photon scheme to reduce the spectral linewidth to less than 200 kHz. This narrow linewidth extends the self-calibrated regime of such sensors by over an order of magnitude, compared to what has been achieved in standard two-photon schemes.
We demonstrate Rydberg atom-based radio frequency sensing with a colinear three-photon scheme in a room temperature cesium vapor cell that minimizes residual Doppler broadening of the probe laser absorption feature. A sub-200 kHz spectral linewidth is observed and extends the self-calibrated Autler-Townes sensing regime to weaker fields by a factor of ~18 compared to the theoretical limit of the most commonly used two-photon scheme. The sensitivity of the method to microsecond pulses is shown to be sufficient to detect radio frequency Rabi frequencies of 2πππ x 0.44 MHz using a 480 kHz bandwidth at 108.9 GHz, demonstrating the ability to sense time-dependent signals suitable for radar and communications.
In this work, we present a high-sensitivity, all-optical, atom-based radio-frequency electrometry technique, implemented via a collinear three-photon excitation scheme in a room-temperature cesium vapor cell. By employing a wave-vector matching condition unique to cesium, our approach reduces the residual Doppler broadening so that it does not dominate the electromagnetically induced absorption linewidth, achieving linewidths below 200 kHz. The narrow linewidth enables the expansion of the self-calibrated Autler-Townes sensing regime and increased sensitivity when compared to methods where Doppler broadening dominates the linewidth. In this paper, we report our latest sensitivity measurements which successfully detected radio-frequency (RF) Rabi frequencies of 2π×43 kHz using a 480 kHz measurement bandwidth at 10.7 GHz, corresponding to a sensitivity of 45 nV/cm/ √ Hz. The results of our experiment show a thirteen-fold improvement compared to our previously reported findings for all-optical atom-based electrometry. Our measurements demonstrate the ability to detect time-varying signals suitable for radar and communication applications with high sensitivity.
In this work, theoretical and experimental works on Rydberg-atom based radio-frequency (RF) sensors are presented. The results were obtained in close collaboration with the Quantum Valley Ideas Lab, whose goal is the miniaturization and prototyping of these sensors. The Rydberg-atom based RF sensors utilize lasers to coherently excite an atomic vapor in a vapor cell at room temperature to a highly excited Rydberg state, which is extremely sensitive to external environmental influences. In this work, Rydberg-atom based RF sensing is described as coherent multi-photon interference in the atom-light coupled system by introducing atom-light coherences. The presence of the RF wave influences the absorption of a probe laser propagating through the atomic medium. The atomic response of the Rydberg-atoms can be engineered by changing the atom-light coherences through laser power and frequency. Analytic expressions for the atomic response to the incident RF wave are derived in the weak probe limit and provide a deeper understanding of the underlying coherent multi-photon interference processes, which help to further tailor the Rydberg-atom for the purpose of the application. Good agreement with full numerical simulations of the Lindblad-master equation is found. An analysis of the various Doppler limits strongly motivates an excitation scheme where the effective wave vector mismatch on the Rydberg transition vanishes, as a promising candidate to achieve narrower spectral linewidths and, consequently, a higher sensitivity. The level structure of cesium presents a unique three-photon excitation scheme where residual Doppler shifts become comparable to the spectral linewidth of the coupling lasers. The experimental realization of this excitation scheme is demonstrated. A spectral linewidth of the Rydberg transition of 190 kHz is achieved. The measurements present the world record sensitivity, 45 nV/cm/Hz^1/2, for all-optical RF sensing with room temperature operation. These results make the three-photon excitation scheme a prime candidate for the next generation of Rydberg-atom based RF sensor prototypes. Finally, all-optical phase-sensitive RF detection is theoretically investigated in a closed-loop excitation scheme. An analytic expression is derived that intuitively describes the atomic response. Furthermore, it provides insights into the probe intensity dynamics that occur when the system is operated under finite detuning. These oscillatory dynamics allow for the extraction of the in- (I) and out- (Q) of-phase response to the RF wave, thereby enabling the simultaneous detection of the RF E-field amplitude and phase. A blueprint for the experimental realization is presented, and angle-of-arrival tolerances for the RF wave are estimated. A quadrature amplitude modulation (QAM) sequence was modelled and the simultaneous extraction of the phase and amplitude of the RF wave of interest was successfully demonstrated.
We describe experiments relevant to Rydberg atom-based sensing. In Rydberg atom-based sensing, atoms contained in a vapor cell are used as a probe of an incident radio frequency electric field. We present a novel approach based on a collinear three-photon read-out and detection scheme, which extends the sensing range of the self-calibrated Autler-Townes sensing mode to lower electric field strengths. We demonstrate proof of concept and present concrete results from first experiments. We show that we are able to measure electric field strengths below 1 mV/cm in the self-calibrated Autler-Townes regime for a radial dipole moment of 2206 ea0for a transition at 10.7 GHz. We measure an Autler-Townes splitting of 503(6) kHz, which is equivalent to a radio frequency electric field strength of micro-V/cm.
Abstract Radio frequency antennas based on Rydberg atom vapor cells can in principle reach sensitivities beyond those of any conventional wire antenna, especially at lower frequencies where very long wires are needed to accommodate the increasing wavelength. They also have other desirable features such as consisting of nonmetallic, hence lower profile, elements. This paper presents a detailed theoretical investigation of Rydberg antenna sensitivity, elucidating parameter regimes that could cumulatively lead to a sensitivity increase 2–3 orders of magnitude beyond that of currently tested configurations. The key insight is to optimally combine the advantages of two well-studied approaches: (i) three laser ‘2D star configuration’ setups that, when enhanced with increased laser power, to some degree compensate for atom motion-induced Doppler broadening, and (ii) resonant coupling between a pair of near-degenerate Rydberg levels, tuned via a local oscillator to the incident signal of interest. The advantage of the star setup is subtle because it only restores the overall sensitivity to the expected Doppler-limited value, compensating for additional significant off-resonance reductions where differently moving atom sub-populations destructively interfere with each other in the net signal. An additional unique advantage of local oscillator tuning is that it leads to vastly narrower line widths, as low as ∼10 kHz set by the intrinsic Rydberg state lifetimes, rather than the typical ∼10 MHz scale set by the core state lifetimes. Intuitively, with this setup the two Rydberg states may be tuned to act as an independent high-q cavity, a point of view supported by a study of the frequency-dependence of the antenna resonant response. There are a number of practical experimental advances, especially larger ∼1 cm laser beam widths, required to suppress various extrinsic line broadening effects and to fully exploit this ‘Rydberg superheterodyne’ response.
The common approach for producing Rydberg atoms in warm vapor cells is with lasers arranged in a counterpropagating, collinear configuration. Doppler effects in these configurations reduce the efficiency of excitation to the Rydberg state while also producing broadened spectral features. In this work, we demonstrate a three-laser Doppler-free excitation using laser beams whose k vectors sum to 0, resulting in an enhancement in the Rydberg density and narrowed spectral features. A three-times enhancement to Rydberg density along with a near four-times reduction in spectroscopic linewidths are observed compared to a collinear configuration. This Doppler-free configuration could prove beneficial to Rydberg atomic technologies, such as electric field sensing with small volumes or deterministic photon sources.