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:2404.04372 · Optica

Strong interactions between integrated microresonators and alkali atomic vapors: towards single-atom, single-photon operation

Roy Zektzer, Xiyuan Lu, Khoi Tuan Hoang, Rahul Shrestha, Sharoon Austin, Feng Lei Zhou, Ashish Chanana, Glenn E. Holland, Daron Westly, Paul D. Lett, Alexey Vyacheslavovich Gorshkov, Kartik A. Srinivasan

Published Sep 3, 2024• 17 citations
arXivHTMLPDF

Abstract

Cavity quantum electrodynamics (cQED), the interaction of a two-level system with a high quality factor ( Q ) cavity, is a foundational building block in different architectures for quantum computation, communication, and metrology. The strong interaction between the atom and the cavity enables single-photon operation, which is required for quantum gates and sources. Cold atoms, quantum dots, and color centers in crystals are among the systems that have shown single-photon operations, but they require significant physical infrastructure. Atomic vapors, on the other hand, require limited experimental infrastructure and are hence much easier to deploy outside a laboratory, but they consist of an ensemble of moving atoms that results in short interaction times involving multiple atoms, which can hamper quantum operations. A solution to this issue can be found in nanophotonic cavities, where the optical mode is confined to a small volume and light-matter interaction is enhanced, so that fast single-atom, single-photon operations are enabled. In this work, we study the interaction of an atomically clad microring resonator (ACMRR) with different-sized ensembles of Rb atoms. We demonstrate strong coupling between an ensemble of ≈50 atoms interacting with a high quality factor ( Q =4.3×10 5 ) ACMRR, yielding a many-atom cooperativity C =(5.5±0.3). We continue to observe signatures of atom-photon interaction for a few (<3) atoms, for which we observe saturation at the level of a few intracavity photons. Further development of our platform, which includes integrated thermo-optic heaters to enable cavity tuning and stabilization, should enable the observation of interactions between single photons and single atoms.

DOI
10.1364/optica.525689

Related papers

Strong interactions between integrated microresonators and alkali atomic vapors: towards single-photon-level operation

Roy Zektzer, Xiyuan Lu, Khoi Tuan Hoang +8 more

We demonstrate strong coupling between an ensemble of ≈50 atoms interacting with a high-Q (>4x105) atomic-cladded microring-resonator, yielding a many-atom cooperativity C≈3.6. We further discuss photonic crystal ring defect resonator development for high single-atom-level cooperativity.

•Jan 1, 2024•0 citations

Strong interactions between integrated photonics and atomic vapors: towards single-photon-level operation

Roy Zektzer, Xiyuan Lu, Khoi Tuan Hoang +7 more

We present recent results aiming to construct single photon sources, detectors and gates using the integration of hot Rubidium atoms and microring resonators (MRRs). We demonstrate strong coupling between an ensemble of ≈53 atoms interacting with a high-Q (>4x10^5) cavity mode, with a many-atom coupling strength g/2pi≈1 GHz and cooperativity C≈3.6 achieved. A peak single-atom cooperativity C0≈0.4 is inferred; to achieve higher cooperativity, we have developed defect mode photonic crystal ring resonators with a 10x reduction in mode volume compared to the MRR while maintaining Q>10^5. Finally, we will discuss theoretical results that support single photon operations using these devices.

Quantum Computing, Communication, and Simulation•Mar 13, 2024•0 citations

Collective strong coupling of thermal atoms to integrated microring resonators

Xiaoyu Cheng, Benyamin Shnirman, Alexandra Kopf +5 more

Strong coupling between atomic ensembles and high-quality optical cavities enables collective and nonlinear phenomena that are central to cavity quantum electrodynamics (cQED). Many experiments have been performed on this topic, with most of them focusing on cold atoms. Here, we experimentally demonstrate collective strong coupling between thermal rubidium vapor and high-quality silicon nitride microring resonators (MRRs) on an integrated photonic chip. We observe cavity-mode splitting, with a measured collective coupling strength of g N / 2 π ≈ 1 G Hz and a collective cooperativity of C N ≈ 2 at 110 ∘ C , indicating coherent energy exchange between the atomic ensemble and the cavity mode despite rapid decoherence in the thermal vapor system. We infer an average of 20 atoms effectively participating in the collective interaction, yielding a single-atom cooperativity of C 0 = 0.1 and approaching the single-atom strong-coupling regime. Our results establish the integrated thermal vapor MRR platform as a robust, compact, and scalable system for studying collective and nonlinear phenomena in cQED.

arXiv:2604.24509•Physical Review Research•Sep 19, 2026•0 citations

Cavity QED based on room temperature atoms interacting with a photonic crystal cavity : a feasibility study

Hadiseh Alaeian, Ralf Ritter, Muamera Basic +2 more

The paradigm of cavity QED is a two-level emitter interacting with a high-quality factor single-mode optical resonator. The hybridization of the emitter and photon wave functions mandates large vacuum Rabi frequencies and long coherence times; features that so far have been successfully realized with trapped cold atoms and ions, and localized solid-state quantum emitters such as superconducting circuits, quantum dots, and color centers Reiserer and Rempe (Rev Modern Phys 87:1379, 2015), Faraon et al. (Phys Rev 81:033838, 2010). Thermal atoms, on the other hand, provide us with a dense emitter ensemble and in comparison to the cold systems are more compatible with integration, hence enabling large-scale quantum systems. However, their thermal motion and large transit-time broadening is a major bottleneck that has to be circumvented. A promising remedy could benefit from the highly controllable and tunable electromagnetic fields of a nano-photonic cavity with strong local electric-field enhancements. Utilizing this feature, here we investigate the interaction between fast moving thermal atoms and a nano-beam photonic crystal cavity (PCC) with large quality factor and small mode volume. Through fully quantum mechanical calculations, including Casimir-Polder potential (i.e. the effect of the surface on radiation properties of an atom), we show, when designed properly, the achievable coupling between the flying atom and the cavity photon would be strong enough to lead to quantum interference effects in spite of short interaction times. In addition, the time-resolved detection of different trajectories can be used to identify single and multiple atom counts. This probabilistic approach will find applications in cavity QED studies in dense atomic media and paves the way towards realizing large-scale, room-temperature macroscopic quantum systems aimed at out of the lab quantum devices.

•Jan 1, 2020•14 citations

Cavity QED based on room temperature atoms interacting with a photonic crystal cavity: a feasibility study

Hadiseh Alaeian, Ralf Ritter, Muamera Basic +2 more

Abstract The paradigm of cavity QED is a two-level emitter interacting with a high-quality factor single-mode optical resonator. The hybridization of the emitter and photon wave functions mandates large vacuum Rabi frequencies and long coherence times; features that so far have been successfully realized with trapped cold atoms and ions, and localized solid-state quantum emitters such as superconducting circuits, quantum dots, and color centers Reiserer and Rempe (Rev Modern Phys 87:1379, 2015), Faraon et al. (Phys Rev 81:033838, 2010). Thermal atoms, on the other hand, provide us with a dense emitter ensemble and in comparison to the cold systems are more compatible with integration, hence enabling large-scale quantum systems. However, their thermal motion and large transit-time broadening is a major bottleneck that has to be circumvented. A promising remedy could benefit from the highly controllable and tunable electromagnetic fields of a nano-photonic cavity with strong local electric-field enhancements. Utilizing this feature, here we investigate the interaction between fast moving thermal atoms and a nano-beam photonic crystal cavity (PCC) with large quality factor and small mode volume. Through fully quantum mechanical calculations, including Casimir–Polder potential (i.e. the effect of the surface on radiation properties of an atom), we show, when designed properly, the achievable coupling between the flying atom and the cavity photon would be strong enough to lead to quantum interference effects in spite of short interaction times. In addition, the time-resolved detection of different trajectories can be used to identify single and multiple atom counts. This probabilistic approach will find applications in cavity QED studies in dense atomic media and paves the way towards realizing large-scale, room-temperature macroscopic quantum systems aimed at out of the lab quantum devices.

arXiv:1907.04680•Applied Physics B•Jan 16, 2020•22 citations

Cavity QED in a high NA resonator

Danial Shadmany, Aishwarya Kumar, Anna Soper +8 more

From fundamental studies of light-matter interaction to applications in quantum networking and sensing, cavity quantum electrodynamics (QED) provides a toolbox to control interactions between atoms and photons. The coherence of interactions is determined by the single-pass atomic absorption and number of photon round-trips. Reducing the cavity loss has enabled resonators supporting 1 million roundtrips but with limited material choices and increased alignment sensitivity. Here, we present a high–numerical aperture, lens-based resonator that pushes the single-atom single-photon absorption probability near its fundamental limit, reducing the mode size at the atom to order λ. This resonator provides a single-atom cooperativity of 1.6 in a cavity where the light circulates ∼10 times. We load single 87 Rb atoms into this cavity, observe strong coupling, and demonstrate cavity-enhanced atom detection with fidelity of 99.55(6)% and survival of 99.89(4)% in 130 μs. Introducing intracavity imaging systems will enable cavity arrays compatible with Rydberg atom array computing technologies, expanding the applicability of the cavity QED toolbox.

Science Advances•Feb 26, 2025•19 citations
Cavity quantum electrodynamics (cQED), the interaction of a two-level system with a high quality factor ( Q ) cavity, is a foundational building block in different architectures for quantum computation, communication, and metrology. The strong interaction between the atom and the cavity enables single-photon operation, which is required for quantum gates and sources. Cold atoms, quantum dots, and color centers in crystals are among the systems that have shown single-photon operations, but they require significant physical infrastructure. Atomic vapors, on the other hand, require limited experimental infrastructure and are hence much easier to deploy outside a laboratory, but they consist of an ensemble of moving atoms that results in short interaction times involving multiple atoms, which can hamper quantum operations. A solution to this issue can be found in nanophotonic cavities, where the optical mode is confined to a small volume and light-matter interaction is enhanced, so that fast single-atom, single-photon operations are enabled. In this work, we study the interaction of an atomically clad microring resonator (ACMRR) with different-sized ensembles of Rb atoms. We demonstrate strong coupling between an ensemble of ≈50 atoms interacting with a high quality factor ( Q =4.3×10 5 ) ACMRR, yielding a many-atom cooperativity C =(5.5±0.3). We continue to observe signatures of atom-photon interaction for a few (<3) atoms, for which we observe saturation at the level of a few intracavity photons. Further development of our platform, which includes integrated thermo-optic heaters to enable cavity tuning and stabilization, should enable the observation of interactions between single photons and single atoms.
We present recent results aiming to construct single photon sources, detectors and gates using the integration of hot Rubidium atoms and microring resonators (MRRs). We demonstrate strong coupling between an ensemble of ≈53 atoms interacting with a high-Q (>4x10^5) cavity mode, with a many-atom coupling strength g/2pi≈1 GHz and cooperativity C≈3.6 achieved. A peak single-atom cooperativity C0≈0.4 is inferred; to achieve higher cooperativity, we have developed defect mode photonic crystal ring resonators with a 10x reduction in mode volume compared to the MRR while maintaining Q>10^5. Finally, we will discuss theoretical results that support single photon operations using these devices.
Strong coupling between atomic ensembles and high-quality optical cavities enables collective and nonlinear phenomena that are central to cavity quantum electrodynamics (cQED). Many experiments have been performed on this topic, with most of them focusing on cold atoms. Here, we experimentally demonstrate collective strong coupling between thermal rubidium vapor and high-quality silicon nitride microring resonators (MRRs) on an integrated photonic chip. We observe cavity-mode splitting, with a measured collective coupling strength of g N / 2 π ≈ 1 G Hz and a collective cooperativity of C N ≈ 2 at 110 ∘ C , indicating coherent energy exchange between the atomic ensemble and the cavity mode despite rapid decoherence in the thermal vapor system. We infer an average of 20 atoms effectively participating in the collective interaction, yielding a single-atom cooperativity of C 0 = 0.1 and approaching the single-atom strong-coupling regime. Our results establish the integrated thermal vapor MRR platform as a robust, compact, and scalable system for studying collective and nonlinear phenomena in cQED.
The paradigm of cavity QED is a two-level emitter interacting with a high-quality factor single-mode optical resonator. The hybridization of the emitter and photon wave functions mandates large vacuum Rabi frequencies and long coherence times; features that so far have been successfully realized with trapped cold atoms and ions, and localized solid-state quantum emitters such as superconducting circuits, quantum dots, and color centers Reiserer and Rempe (Rev Modern Phys 87:1379, 2015), Faraon et al. (Phys Rev 81:033838, 2010). Thermal atoms, on the other hand, provide us with a dense emitter ensemble and in comparison to the cold systems are more compatible with integration, hence enabling large-scale quantum systems. However, their thermal motion and large transit-time broadening is a major bottleneck that has to be circumvented. A promising remedy could benefit from the highly controllable and tunable electromagnetic fields of a nano-photonic cavity with strong local electric-field enhancements. Utilizing this feature, here we investigate the interaction between fast moving thermal atoms and a nano-beam photonic crystal cavity (PCC) with large quality factor and small mode volume. Through fully quantum mechanical calculations, including Casimir-Polder potential (i.e. the effect of the surface on radiation properties of an atom), we show, when designed properly, the achievable coupling between the flying atom and the cavity photon would be strong enough to lead to quantum interference effects in spite of short interaction times. In addition, the time-resolved detection of different trajectories can be used to identify single and multiple atom counts. This probabilistic approach will find applications in cavity QED studies in dense atomic media and paves the way towards realizing large-scale, room-temperature macroscopic quantum systems aimed at out of the lab quantum devices.
Abstract The paradigm of cavity QED is a two-level emitter interacting with a high-quality factor single-mode optical resonator. The hybridization of the emitter and photon wave functions mandates large vacuum Rabi frequencies and long coherence times; features that so far have been successfully realized with trapped cold atoms and ions, and localized solid-state quantum emitters such as superconducting circuits, quantum dots, and color centers Reiserer and Rempe (Rev Modern Phys 87:1379, 2015), Faraon et al. (Phys Rev 81:033838, 2010). Thermal atoms, on the other hand, provide us with a dense emitter ensemble and in comparison to the cold systems are more compatible with integration, hence enabling large-scale quantum systems. However, their thermal motion and large transit-time broadening is a major bottleneck that has to be circumvented. A promising remedy could benefit from the highly controllable and tunable electromagnetic fields of a nano-photonic cavity with strong local electric-field enhancements. Utilizing this feature, here we investigate the interaction between fast moving thermal atoms and a nano-beam photonic crystal cavity (PCC) with large quality factor and small mode volume. Through fully quantum mechanical calculations, including Casimir–Polder potential (i.e. the effect of the surface on radiation properties of an atom), we show, when designed properly, the achievable coupling between the flying atom and the cavity photon would be strong enough to lead to quantum interference effects in spite of short interaction times. In addition, the time-resolved detection of different trajectories can be used to identify single and multiple atom counts. This probabilistic approach will find applications in cavity QED studies in dense atomic media and paves the way towards realizing large-scale, room-temperature macroscopic quantum systems aimed at out of the lab quantum devices.
From fundamental studies of light-matter interaction to applications in quantum networking and sensing, cavity quantum electrodynamics (QED) provides a toolbox to control interactions between atoms and photons. The coherence of interactions is determined by the single-pass atomic absorption and number of photon round-trips. Reducing the cavity loss has enabled resonators supporting 1 million roundtrips but with limited material choices and increased alignment sensitivity. Here, we present a high–numerical aperture, lens-based resonator that pushes the single-atom single-photon absorption probability near its fundamental limit, reducing the mode size at the atom to order λ. This resonator provides a single-atom cooperativity of 1.6 in a cavity where the light circulates ∼10 times. We load single 87 Rb atoms into this cavity, observe strong coupling, and demonstrate cavity-enhanced atom detection with fidelity of 99.55(6)% and survival of 99.89(4)% in 130 μs. Introducing intracavity imaging systems will enable cavity arrays compatible with Rydberg atom array computing technologies, expanding the applicability of the cavity QED toolbox.