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:1705.05700 · Physical Review A

Microwave-to-optical frequency conversion using a cesium atom coupled to a superconducting resonator

Bryan Gard, Kurt A. Jacobs, R. McDermott, Mark E. Saffman

Published Jul 18, 2017• 72 citations
arXivHTMLPDF

Abstract

A candidate for converting quantum information from microwave to optical frequencies is the use of a single atom that interacts with a superconducting microwave resonator on one hand and an optical cavity on the other. The large electric dipole moments and microwave transition frequencies possessed by Rydberg states allow them to couple strongly to superconducting devices. Lasers can then be used to connect a Rydberg transition to an optical transition to realize the conversion. Since the fundamental source of noise in this process is spontaneous emission from the atomic levels, the resulting control problem involves choosing the pulse shapes of the driving lasers so as to maximize the transfer rate while minimizing this loss. Here we consider the concrete example of a cesium atom, along with two specific choices for the levels to be used in the conversion cycle. Under the assumption that spontaneous emission is the only significant source of errors, we use numerical optimization to determine the likely rates for reliable quantum communication that could be achieved with this device. These rates are on the order of a few megaqubits per second.

DOI
10.1103/physreva.96.013833

Related papers

Robust microwave-to-optical single-photon conversion with a Rydberg atom

Wanrang Yu, Thibault Vogt

Abstract We propose an efficient scheme for microwave-to-optical quantum frequency conversion mediated by a single atom simultaneously coupled to a superconducting microwave resonator and an optical cavity. The atom mediates efficient interactions between the two electromagnetic modes via non-linear frequency mixing owing to the presence of huge microwave transition dipole moments between nearby Rydberg states as well as suitable optical transitions between low-lying states. In the regime of four-wave mixing with off-resonant fields, the excited states can be adiabatically eliminated, leading to an effective Hamiltonian that directly describes the two-mode interaction responsible for the frequency conversion. However, in this regime, the converter is slow, hence sensitive to losses due to cavity decays. To enhance the performance of the conversion process, we employ pulse engineering to tailor the atom-field couplings. The resulting protocol exhibits high robustness against decoherence and parameter fluctuations, making it well suited for realistic experimental implementations. Our scheme provides a promising route toward high-fidelity and scalable hybrid quantum interfaces connecting superconducting and optical quantum networks.

Laser Physics Letters•Jul 1, 2026•0 citations

Microwave to optical conversion with atoms on a superconducting chip

David Petrosyan, Klaus Mølmer, József Fortágh +1 more

Abstract We describe a scheme to coherently convert a microwave photon of a superconducting co-planar waveguide resonator to an optical photon emitted into a well-defined temporal and spatial mode. The conversion is realized by a cold atomic ensemble trapped close the surface of the superconducting atom chip, near the antinode of the microwave cavity. The microwave photon couples to a strong Rydberg transition of the atoms that are also driven by a pair of laser fields with appropriate frequencies and wavevectors for an efficient wave-mixing process. With only several thousand atoms in an ensemble of moderate density, the microwave photon can be completely converted into an optical photon emitted with high probability into the phase matched direction and, e.g. fed into a fiber waveguide. This scheme operates in a free-space configuration, without requiring strong coupling of the atoms to a resonant optical cavity.

arXiv:1904.09197•New Journal of Physics•Jul 1, 2019•49 citations

Microwave-to-optical transduction with erbium ions coupled to planar photonic and superconducting resonators

Jake Rochman, Tian Xie, John G. Bartholomew +2 more

Abstract Optical quantum networks can connect distant quantum processors to enable secure quantum communication and distributed quantum computing. Superconducting qubits are a leading technology for quantum information processing but cannot couple to long-distance optical networks without an efficient, coherent, and low noise interface between microwave and optical photons. Here, we demonstrate a microwave-to-optical transducer using an ensemble of erbium ions that is simultaneously coupled to a superconducting microwave resonator and a nanophotonic optical resonator. The coherent atomic transitions of the ions mediate the frequency conversion from microwave photons to optical photons and using photon counting we observed device conversion efficiency approaching 10 −7 . With pulsed operation at a low duty cycle, the device maintained a spin temperature below 100 mK and microwave resonator heating of less than 0.15 quanta.

Nature Communications•Mar 1, 2023•48 citations

Efficient quantum microwave-to-optical conversion using electro-optic nanophotonic coupled resonators

Mohammad Soltani, Mian Zhang, Colm A. Ryan +3 more

We propose a low-noise, triply resonant, electro-optic (EO) scheme for quantum microwave-to-optical conversion based on coupled nanophotonics resonators integrated with a superconducting qubit. Our optical system features a split resonance---a doublet---with a tunable frequency splitting that matches the microwave resonance frequency of the superconducting qubit. This is in contrast to conventional approaches, where large optical resonators with free-spectral range comparable to the qubit microwave frequency are used. In our system, EO mixing between the optical pump coupled into the low-frequency doublet mode and a resonance microwave photon results in an up-converted optical photon on resonance with high-frequency doublet mode. Importantly, the down-conversion process, which is the source of noise, is suppressed in our scheme as the coupled-resonator system does not support modes at that frequency. Our device has at least an order of magnitude smaller footprint than conventional devices, resulting in large overlap between optical and microwave fields and a large photon conversion rate ($g/2\ensuremath{\pi}$) in the range of $\ensuremath{\sim}5$--15 kHz. Owing to a large $g$ factor and doubly resonant nature of our device, microwave-to-optical frequency conversion can be achieved with optical pump powers in the range of tens of microwatts, even with moderate values for optical $\mathit{Q}$ ($\ensuremath{\sim}{10}^{6}$) and microwave $Q$ ($\ensuremath{\sim}{10}^{4}$). The performance metrics of our device, with substantial improvement over the previous EO-based approaches, promise a scalable quantum microwave-to-optical conversion and networking of superconducting processors via optical fiber communication.

arXiv:1711.00346•Physical Review A•Oct 5, 2017•79 citations

Coupling Rydberg atoms to superconducting microwave circuits

A. A. Morgan

A hybrid circuit quantum electro-dynamics (circuit QED) setup consisting of helium atoms in high-n Rydberg states and superconducting co-planar waveguide (CPW) microwave resonators has been developed with the goal of performing hybrid quantum optics experiments with applications in quantum information processing. In this thesis an overview of the field of cavity QED is introduced, and numerical methods to calculate the atomic energy level structure and transition dipole moments in electric and magnetic fields are described. Using this background information, a new method for efficiently preparing high-n circular Rydberg states is presented. This was required to ac- cess circular-state–to–circular-state transition frequencies in experiments which are compatible with superconducting CPW microwave resonators. Experimental and numerical results demonstrating the implementation of this method for the preparation of the |n = 70, l = 69, ml = +69⟩ circular state in helium are reported. The design and fabrication of λ/4 superconducting CPW microwave resonators, compatible with these high-n circular Rydberg states of helium is then described. The effects of microwave driving power, temperature and magnetic field on the characteristics of these resonators are presented. Finally, experiments in which helium Rydberg atoms have been coherently coupled to the microwave field of a superconducting co-planar waveguide resonator are reported.

•Apr 28, 2020•0 citations

Interfacing Rydberg atoms with a chip-based superconducting microwave resonator using an ac-Stark-shifted single-photon transition

L. L. Brown, I. K. Bhangoo, S. D. Hogan

Helium atoms in the 1 s 50 s S 1 3 Rydberg level have been resonantly coupled to the 2 π × 11.722 GHz second harmonic mode of a chip-based superconducting coplanar wave-guide microwave resonator. To achieve this, the single-photon electric-dipole-allowed 1 s 50 s S 1 3 → 1 s 50 p P J 3 transition was tuned into resonance with the resonator mode through the ac Stark shift induced by a second strong 2 π × 3.350 GHz microwave dressing field. The effects of this dressing field, and residual uncanceled dc electric fields at the location of the atoms close to the superconducting chip surface were interpreted with support from Floquet calculations of the energy level structure of the Rydberg states. To observe appreciable population transfer in the 1 µ s atom-resonator interaction time using this transition, which had an electric dipole moment of 1500 e a 0 , pulsed microwave fields were injected into the resonator. From the photon occupation number in the resonator mode under these conditions, the single-photon Rabi frequency associated with the coupling of the atoms to the resonator was estimated to be ∼ 2 π × 100 Hz . These results represent an important step toward operation of this Rydberg-atom–superconducting-circuit interface in the single-photon strong-coupling regime.

arXiv:2508.20292•Physical Review A•Dec 17, 2025•1 citation
A candidate for converting quantum information from microwave to optical frequencies is the use of a single atom that interacts with a superconducting microwave resonator on one hand and an optical cavity on the other. The large electric dipole moments and microwave transition frequencies possessed by Rydberg states allow them to couple strongly to superconducting devices. Lasers can then be used to connect a Rydberg transition to an optical transition to realize the conversion. Since the fundamental source of noise in this process is spontaneous emission from the atomic levels, the resulting control problem involves choosing the pulse shapes of the driving lasers so as to maximize the transfer rate while minimizing this loss. Here we consider the concrete example of a cesium atom, along with two specific choices for the levels to be used in the conversion cycle. Under the assumption that spontaneous emission is the only significant source of errors, we use numerical optimization to determine the likely rates for reliable quantum communication that could be achieved with this device. These rates are on the order of a few megaqubits per second.
Abstract We propose an efficient scheme for microwave-to-optical quantum frequency conversion mediated by a single atom simultaneously coupled to a superconducting microwave resonator and an optical cavity. The atom mediates efficient interactions between the two electromagnetic modes via non-linear frequency mixing owing to the presence of huge microwave transition dipole moments between nearby Rydberg states as well as suitable optical transitions between low-lying states. In the regime of four-wave mixing with off-resonant fields, the excited states can be adiabatically eliminated, leading to an effective Hamiltonian that directly describes the two-mode interaction responsible for the frequency conversion. However, in this regime, the converter is slow, hence sensitive to losses due to cavity decays. To enhance the performance of the conversion process, we employ pulse engineering to tailor the atom-field couplings. The resulting protocol exhibits high robustness against decoherence and parameter fluctuations, making it well suited for realistic experimental implementations. Our scheme provides a promising route toward high-fidelity and scalable hybrid quantum interfaces connecting superconducting and optical quantum networks.
Abstract We describe a scheme to coherently convert a microwave photon of a superconducting co-planar waveguide resonator to an optical photon emitted into a well-defined temporal and spatial mode. The conversion is realized by a cold atomic ensemble trapped close the surface of the superconducting atom chip, near the antinode of the microwave cavity. The microwave photon couples to a strong Rydberg transition of the atoms that are also driven by a pair of laser fields with appropriate frequencies and wavevectors for an efficient wave-mixing process. With only several thousand atoms in an ensemble of moderate density, the microwave photon can be completely converted into an optical photon emitted with high probability into the phase matched direction and, e.g. fed into a fiber waveguide. This scheme operates in a free-space configuration, without requiring strong coupling of the atoms to a resonant optical cavity.
Abstract Optical quantum networks can connect distant quantum processors to enable secure quantum communication and distributed quantum computing. Superconducting qubits are a leading technology for quantum information processing but cannot couple to long-distance optical networks without an efficient, coherent, and low noise interface between microwave and optical photons. Here, we demonstrate a microwave-to-optical transducer using an ensemble of erbium ions that is simultaneously coupled to a superconducting microwave resonator and a nanophotonic optical resonator. The coherent atomic transitions of the ions mediate the frequency conversion from microwave photons to optical photons and using photon counting we observed device conversion efficiency approaching 10 −7 . With pulsed operation at a low duty cycle, the device maintained a spin temperature below 100 mK and microwave resonator heating of less than 0.15 quanta.
We propose a low-noise, triply resonant, electro-optic (EO) scheme for quantum microwave-to-optical conversion based on coupled nanophotonics resonators integrated with a superconducting qubit. Our optical system features a split resonance---a doublet---with a tunable frequency splitting that matches the microwave resonance frequency of the superconducting qubit. This is in contrast to conventional approaches, where large optical resonators with free-spectral range comparable to the qubit microwave frequency are used. In our system, EO mixing between the optical pump coupled into the low-frequency doublet mode and a resonance microwave photon results in an up-converted optical photon on resonance with high-frequency doublet mode. Importantly, the down-conversion process, which is the source of noise, is suppressed in our scheme as the coupled-resonator system does not support modes at that frequency. Our device has at least an order of magnitude smaller footprint than conventional devices, resulting in large overlap between optical and microwave fields and a large photon conversion rate ($g/2\ensuremath{\pi}$) in the range of $\ensuremath{\sim}5$--15 kHz. Owing to a large ggg factor and doubly resonant nature of our device, microwave-to-optical frequency conversion can be achieved with optical pump powers in the range of tens of microwatts, even with moderate values for optical Q\mathit{Q}Q ($\ensuremath{\sim}{10}^{6}$) and microwave QQQ ($\ensuremath{\sim}{10}^{4}$). The performance metrics of our device, with substantial improvement over the previous EO-based approaches, promise a scalable quantum microwave-to-optical conversion and networking of superconducting processors via optical fiber communication.
A hybrid circuit quantum electro-dynamics (circuit QED) setup consisting of helium atoms in high-n Rydberg states and superconducting co-planar waveguide (CPW) microwave resonators has been developed with the goal of performing hybrid quantum optics experiments with applications in quantum information processing. In this thesis an overview of the field of cavity QED is introduced, and numerical methods to calculate the atomic energy level structure and transition dipole moments in electric and magnetic fields are described. Using this background information, a new method for efficiently preparing high-n circular Rydberg states is presented. This was required to ac- cess circular-state–to–circular-state transition frequencies in experiments which are compatible with superconducting CPW microwave resonators. Experimental and numerical results demonstrating the implementation of this method for the preparation of the |n = 70, l = 69, ml = +69⟩ circular state in helium are reported. The design and fabrication of λ/4 superconducting CPW microwave resonators, compatible with these high-n circular Rydberg states of helium is then described. The effects of microwave driving power, temperature and magnetic field on the characteristics of these resonators are presented. Finally, experiments in which helium Rydberg atoms have been coherently coupled to the microwave field of a superconducting co-planar waveguide resonator are reported.
Helium atoms in the 1 s 50 s S 1 3 Rydberg level have been resonantly coupled to the 2 π × 11.722 GHz second harmonic mode of a chip-based superconducting coplanar wave-guide microwave resonator. To achieve this, the single-photon electric-dipole-allowed 1 s 50 s S 1 3 → 1 s 50 p P J 3 transition was tuned into resonance with the resonator mode through the ac Stark shift induced by a second strong 2 π × 3.350 GHz microwave dressing field. The effects of this dressing field, and residual uncanceled dc electric fields at the location of the atoms close to the superconducting chip surface were interpreted with support from Floquet calculations of the energy level structure of the Rydberg states. To observe appreciable population transfer in the 1 µ s atom-resonator interaction time using this transition, which had an electric dipole moment of 1500 e a 0 , pulsed microwave fields were injected into the resonator. From the photon occupation number in the resonator mode under these conditions, the single-photon Rabi frequency associated with the coupling of the atoms to the resonator was estimated to be ∼ 2 π × 100 Hz . These results represent an important step toward operation of this Rydberg-atom–superconducting-circuit interface in the single-photon strong-coupling regime.