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

Physics

A Single-Atom Optical Switch

Darrick E. Chang

Published Nov 4, 2013• 1 citation
Publisher

Abstract

We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom.The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers.This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum.We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output.We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection.Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.

DOI
10.1103/physics.6.121

Related papers

Fiber-Optical Switch Controlled by a Single Atom

Danny G. O’Shea, Christian Junge, Jürgen Volz +1 more

We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom. The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers. This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum. We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output. We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection. Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.

arXiv:1306.1357•Physical Review Letters•Nov 4, 2013•190 citations

Microtoroidal cavity QED with fiber overcoupling and strong atom-field coupling: A single-atom quantum switch for coherent light fields

A. S. Parkins, Takao Aoki

We propose a scheme for single-atom, quantum control of the direction of propagation of a coherent field incident, via a tapered fiber, upon a microtoroidal whispering-gallery-mode (WGM) resonator. The scheme involves overcoupling of the fiber taper to the resonator and strong coupling of an atom to the evanescent field of the WGM, i.e., an atom-field coupling that exceeds the total WGM linewidth. In contrast to previous, related schemes that operate in the bad-cavity regime, the proposed scheme can operate effectively with much stronger incident fields, while also preserving their coherent nature. It can also serve to prepare an entangled state of the atom and coherent optical pulses propagating in opposite directions along the fiber. We evaluate the fidelity of preparation of such a state taking into account absorption and atomic spontaneous emission and demonstrate that high fidelities should be possible with realistic parameters.

arXiv:1405.6776•Physical Review A•Nov 11, 2014•20 citations

Coupling a Single Trapped Atom to a Whispering-Gallery-Mode Microresonator

Elisa Will, Luke Masters, Arno Rauschenbeutel +2 more

We demonstrate trapping of a single ^{85}Rb atom at a distance of about 200 nm from the surface of a whispering-gallery-mode bottle microresonator. The atom is trapped in an optical potential, which is created by retroreflecting a red-detuned focused laser beam from the resonator surface. We counteract the trap-induced light shift of the atomic transition frequency by superposing a second laser beam. This allows us to observe a vacuum Rabi splitting in the excitation spectrum of the coupled atom-resonator system. This first demonstration of stable and controlled interaction of a single atom with a whispering-gallery mode in the strong coupling regime opens up the route toward the implementation of quantum protocols and applications that harvest the chiral atom-light coupling present in this class of resonators.

arXiv:2010.07267•Physical Review Letters•Jun 11, 2021•69 citations

Quantum optical circulator controlled by a single chirally coupled atom

Jürgen Volz, Michael Scheucher, Adèle Hilico +2 more

Here we demonstrate the experimental realization of a fiber-integrated optical circulator whose operation direction is controlled by the quantum state of a single atom. The device is based on a bottle whispering-gallery-mode microresonator interfaced by two optical nanofibers. Depending on its internal state, the single atom couples differently to the chiral resonator fields. This results in a direction dependent transmission through the resonator and thus realizes an optical circulator. The demonstrated quantum optical circulator opens new ways for routing and processing quantum information in optical circuits.

International Conference on Transparent Optical Networks•Jul 1, 2017•8 citations

Efficient Routing of Single Photons by One Atom and a Microtoroidal Cavity

Takao Aoki, A. S. Parkins, Daniel J. Alton +5 more

Single photons from a coherent input are efficiently redirected to a separate output by way of a fiber-coupled microtoroidal cavity interacting with individual cesium atoms. By operating in an overcoupled regime for the input-output to a tapered fiber, our system functions as a quantum router with high efficiency for photon sorting. Single photons are reflected and excess photons transmitted, as confirmed by observations of photon antibunching (bunching) for the reflected (transmitted) light. Our photon router is robust against large variations of atomic position and input power, with the observed photon antibunching persisting for intracavity photon number 0.03 < or approximately similar n < or approximately similar 0.7.

arXiv:0901.0836•Physical Review Letters•Feb 27, 2009•266 citations

Strong coupling between single atoms and non-transversal photons

Jürgen Volz, C. Junge, Danny G. O’Shea +1 more

The interaction between single quantum emitters and non-transversally polarized photons for which the electric field vector amplitude has a significant component in the direction of propagation is investigated. Even though this situation seems to be at odds with the description of light as a transverse wave, it regularly occurs when interfacing or manipulating emitters with non-paraxial, guided, or evanescent light. Here, this phenomenon for the case of single atoms that strongly interact with whispering-gallery-mode (WGM) microresonators is quantitatively investigated. These resonators confine light by continuous total internal reflection and offer the advantage of very long photon lifetimes in conjunction with near-lossless in- and out-coupling of light via tapered fiber couplers. In the setup, a novel type of high-Q WGM microresonator - a so-called bottle microresonator, which has the additional advantage of being fully tunable and provides a mode geometry that enables near-lossless simultaneous coupling of two independent tapered fiber couplers, is employed.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•May 1, 2013•16 citations
We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom.The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers.This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum.We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output.We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection.Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.
We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom. The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers. This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum. We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output. We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection. Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.
We propose a scheme for single-atom, quantum control of the direction of propagation of a coherent field incident, via a tapered fiber, upon a microtoroidal whispering-gallery-mode (WGM) resonator. The scheme involves overcoupling of the fiber taper to the resonator and strong coupling of an atom to the evanescent field of the WGM, i.e., an atom-field coupling that exceeds the total WGM linewidth. In contrast to previous, related schemes that operate in the bad-cavity regime, the proposed scheme can operate effectively with much stronger incident fields, while also preserving their coherent nature. It can also serve to prepare an entangled state of the atom and coherent optical pulses propagating in opposite directions along the fiber. We evaluate the fidelity of preparation of such a state taking into account absorption and atomic spontaneous emission and demonstrate that high fidelities should be possible with realistic parameters.
We demonstrate trapping of a single ^{85}Rb atom at a distance of about 200 nm from the surface of a whispering-gallery-mode bottle microresonator. The atom is trapped in an optical potential, which is created by retroreflecting a red-detuned focused laser beam from the resonator surface. We counteract the trap-induced light shift of the atomic transition frequency by superposing a second laser beam. This allows us to observe a vacuum Rabi splitting in the excitation spectrum of the coupled atom-resonator system. This first demonstration of stable and controlled interaction of a single atom with a whispering-gallery mode in the strong coupling regime opens up the route toward the implementation of quantum protocols and applications that harvest the chiral atom-light coupling present in this class of resonators.
Here we demonstrate the experimental realization of a fiber-integrated optical circulator whose operation direction is controlled by the quantum state of a single atom. The device is based on a bottle whispering-gallery-mode microresonator interfaced by two optical nanofibers. Depending on its internal state, the single atom couples differently to the chiral resonator fields. This results in a direction dependent transmission through the resonator and thus realizes an optical circulator. The demonstrated quantum optical circulator opens new ways for routing and processing quantum information in optical circuits.
Single photons from a coherent input are efficiently redirected to a separate output by way of a fiber-coupled microtoroidal cavity interacting with individual cesium atoms. By operating in an overcoupled regime for the input-output to a tapered fiber, our system functions as a quantum router with high efficiency for photon sorting. Single photons are reflected and excess photons transmitted, as confirmed by observations of photon antibunching (bunching) for the reflected (transmitted) light. Our photon router is robust against large variations of atomic position and input power, with the observed photon antibunching persisting for intracavity photon number 0.03 < or approximately similar n < or approximately similar 0.7.
The interaction between single quantum emitters and non-transversally polarized photons for which the electric field vector amplitude has a significant component in the direction of propagation is investigated. Even though this situation seems to be at odds with the description of light as a transverse wave, it regularly occurs when interfacing or manipulating emitters with non-paraxial, guided, or evanescent light. Here, this phenomenon for the case of single atoms that strongly interact with whispering-gallery-mode (WGM) microresonators is quantitatively investigated. These resonators confine light by continuous total internal reflection and offer the advantage of very long photon lifetimes in conjunction with near-lossless in- and out-coupling of light via tapered fiber couplers. In the setup, a novel type of high-Q WGM microresonator - a so-called bottle microresonator, which has the additional advantage of being fully tunable and provides a mode geometry that enables near-lossless simultaneous coupling of two independent tapered fiber couplers, is employed.