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Hinney J, Prasad AS, Mahmoodian S, Hammerer K, Rauschenbeutel A, Schneeweiss P, Volz J, Schemmer M. Unraveling Two-Photon Entanglement via the Squeezing Spectrum of Light Traveling through Nanofiber-Coupled Atoms. Phys Rev Lett 2021; 127:123602. [PMID: 34597106 DOI: 10.1103/physrevlett.127.123602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
We observe that a weak guided light field transmitted through an ensemble of atoms coupled to an optical nanofiber exhibits quadrature squeezing. From the measured squeezing spectrum we gain direct access to the phase and amplitude of the energy-time entangled part of the two-photon wave function which arises from the strongly correlated transport of photons through the ensemble. For small atomic ensembles we observe a spectrum close to the line shape of the atomic transition, while sidebands are observed for sufficiently large ensembles, in agreement with our theoretical predictions. Furthermore, we vary the detuning of the probe light with respect to the atomic resonance and infer the phase of the entangled two-photon wave function. From the amplitude and the phase of the spectrum, we reconstruct the real and imaginary part of the time-domain wave function. Our characterization of the entangled two-photon component constitutes a diagnostic tool for quantum optics devices.
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Affiliation(s)
- Jakob Hinney
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
| | - Adarsh S Prasad
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
| | - Sahand Mahmoodian
- Institute for Theoretical Physics, Institute for Gravitational Physics (Albert Einstein Institute), Leibniz University Hannover, Appelstraße 2, 30167 Hannover, Germany
| | - Klemens Hammerer
- Institute for Theoretical Physics, Institute for Gravitational Physics (Albert Einstein Institute), Leibniz University Hannover, Appelstraße 2, 30167 Hannover, Germany
| | - Arno Rauschenbeutel
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Philipp Schneeweiss
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Jürgen Volz
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Max Schemmer
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
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2
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Zhang T, Jones P, Smetana J, Miao H, Martynov D, Freise A, Ballmer SW. Two-Carrier Scheme: Evading the 3 dB Quantum Penalty of Heterodyne Readout in Gravitational-Wave Detectors. Phys Rev Lett 2021; 126:221301. [PMID: 34152184 DOI: 10.1103/physrevlett.126.221301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/06/2020] [Accepted: 05/05/2021] [Indexed: 06/13/2023]
Abstract
Precision measurements using a traditional heterodyne readout suffer a 3 dB quantum noise penalty compared with a homodyne readout. The extra noise is caused by the quantum fluctuations in the image vacuum. We propose a two-carrier gravitational-wave detector design that evades the 3 dB quantum penalty of the heterodyne readout. We further propose a new way of realizing frequency-dependent squeezing utilizing two-mode squeezing in our scheme. It naturally achieves more precise audio frequency signal measurements with radio frequency squeezing. In addition, the detector is compatible with other quantum nondemolition techniques.
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Affiliation(s)
- Teng Zhang
- School of Physics and Astronomy, and Institute of Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Philip Jones
- School of Physics and Astronomy, and Institute of Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jiří Smetana
- School of Physics and Astronomy, and Institute of Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Haixing Miao
- School of Physics and Astronomy, and Institute of Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Denis Martynov
- School of Physics and Astronomy, and Institute of Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Andreas Freise
- School of Physics and Astronomy, and Institute of Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
- Department of Physics and Astronomy, VU Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
- Nikhef, Science Park 105, 1098 XG Amsterdam, Netherlands
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3
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Hümmer D, Romero-Isart O, Rauschenbeutel A, Schneeweiss P. Probing Surface-Bound Atoms with Quantum Nanophotonics. Phys Rev Lett 2021; 126:163601. [PMID: 33961459 DOI: 10.1103/physrevlett.126.163601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Quantum control of atoms at ultrashort distances from surfaces would open a new paradigm in quantum optics and offer a novel tool for the investigation of near-surface physics. Here, we investigate the motional states of atoms that are bound weakly to the surface of a hot optical nanofiber. We theoretically demonstrate that with optimized mechanical properties of the nanofiber these states are quantized despite phonon-induced decoherence. We further show that it is possible to influence their properties with additional nanofiber-guided light fields and suggest heterodyne fluorescence spectroscopy to probe the spectrum of the quantized atomic motion. Extending the optical control of atoms to smaller atom-surface separations could create opportunities for quantum communication and instigate the convergence of surface physics, quantum optics, and the physics of cold atoms.
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Affiliation(s)
- Daniel Hümmer
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria
- Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - Oriol Romero-Isart
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria
- Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - Arno Rauschenbeutel
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Philipp Schneeweiss
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
- Atominstitut, TU Wien, 1020 Vienna, Austria
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4
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Wang X, Zhang P, Li G, Zhang T. High-efficiency coupling of single quantum emitters into hole-tailored nanofibers. Opt Express 2021; 29:11158-11168. [PMID: 33820234 DOI: 10.1364/oe.420243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
We propose a scheme to enhance the coupling efficiency of photons from a single quantum emitter into a hole-tailored nanofiber. The single quantum emitter is positioned inside a circular hole etched along the radial axis of the nanofiber. The coupling efficiency can be effectively enhanced and is twice as high as the case in which only an intact nanofiber without the hole is used. The effective enhancement independent of a cavity can avoid the selection of a single emitter for the specific wavelength, which means a broad operating wavelength range. Numerical simulations are performed to optimize the coupling efficiency by setting appropriate diameters of the nanofiber and the hole. The simulation results show that the coupling efficiency can reach 62.8% when the single quantum emitter with azimuthal polarization (x direction) is at a position 200 nm from the middle of the hole along the hole-axial direction. The diameters of the nanofiber and the hole are 800 nm and 400 nm, respectively, while the wavelength of the single quantum emitter is 852 nm. Hole-tailored nanofibers have a simple configuration and are easy to fabricate and integrate with other micro/nanophotonic structures; this fiber structure has wide application prospects in quantum information processing and quantum precision measurement.
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5
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Meng Y, Liedl C, Pucher S, Rauschenbeutel A, Schneeweiss P. Imaging and Localizing Individual Atoms Interfaced with a Nanophotonic Waveguide. Phys Rev Lett 2020; 125:053603. [PMID: 32794877 DOI: 10.1103/physrevlett.125.053603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Single particle-resolved fluorescence imaging is an enabling technology in cold-atom physics. However, so far, this technique has not been available for nanophotonic atom-light interfaces. Here, we image single atoms that are trapped and optically interfaced using an optical nanofiber. Near-resonant light is scattered off the atoms and imaged while counteracting heating mechanisms via degenerate Raman cooling. We detect trapped atoms within 150 ms and record image sequences of given atoms. Building on our technique, we perform two experiments which are conditioned on the number and position of the nanofiber-trapped atoms. We measure the transmission of nanofiber-guided resonant light and verify its exponential scaling in the few-atom limit, in accordance with Beer-Lambert's law. Moreover, depending on the interatomic distance, we observe interference of the fields that two simultaneously trapped atoms emit into the nanofiber. The demonstrated technique enables postselection and possible feedback schemes and thereby opens the road toward a new generation of experiments in quantum nanophotonics.
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Affiliation(s)
- Y Meng
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - C Liedl
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - S Pucher
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - A Rauschenbeutel
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - P Schneeweiss
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
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6
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Hobson R, Bowden W, Vianello A, Hill IR, Gill P. Cavity-enhanced non-destructive detection of atoms for an optical lattice clock. Opt Express 2019; 27:37099-37110. [PMID: 31878496 DOI: 10.1364/oe.27.037099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate a new method of cavity-enhanced non-destructive detection of atoms for a strontium optical lattice clock. The detection scheme is shown to be linear in atom number up to at least 2×104 atoms, to reject technical noise sources, to achieve signal to noise ratio close to the photon shot noise limit, to provide spatially uniform atom-cavity coupling, and to minimize inhomogeneous ac Stark shifts. These features enable detection of atoms with minimal perturbation to the atomic state, a critical step towards realizing an ultra-high-stability, quantum-enhanced optical lattice clock.
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7
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González-Tudela A, Muñoz CS, Cirac JI. Engineering and Harnessing Giant Atoms in High-Dimensional Baths: A Proposal for Implementation with Cold Atoms. Phys Rev Lett 2019; 122:203603. [PMID: 31172782 DOI: 10.1103/physrevlett.122.203603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Indexed: 06/09/2023]
Abstract
Emitters coupled simultaneously to distant positions of a photonic bath, the so-called giant atoms, represent a new paradigm in quantum optics. When coupled to one-dimensional baths, as recently implemented with transmission lines or SAW waveguides, they lead to striking effects such as chiral emission or decoherence-free atomic interactions. Here, we show how to create giant atoms in dynamical state-dependent optical lattices, which offers the possibility of coupling them to structured baths in arbitrary dimensions. This opens up new avenues to a variety of phenomena and opportunities for quantum simulation. In particular, we show how to engineer unconventional radiation patterns, like multidirectional chiral emission, as well as collective interactions that can be used to simulate nonequilibrium many-body dynamics with no analog in other setups. Additionally, the recipes we provide to harness giant atoms in high dimensions can be exported to other platforms where such nonlocal couplings can be engineered.
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Affiliation(s)
- A González-Tudela
- Instituto de Física Fundamental IFF-CSIC, Calle Serrano 113b, Madrid 28006, Spain
| | - C Sánchez Muñoz
- Clarendon Laboratory, University of Oxford, Oxford OX13PU, United Kingdom
| | - J I Cirac
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Str. 1. 85748 Garching, Germany
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8
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Kato S, Német N, Senga K, Mizukami S, Huang X, Parkins S, Aoki T. Observation of dressed states of distant atoms with delocalized photons in coupled-cavities quantum electrodynamics. Nat Commun 2019; 10:1160. [PMID: 30858381 DOI: 10.1038/s41467-019-08975-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/28/2019] [Indexed: 11/11/2022] Open
Abstract
In a cavity quantum electrodynamics (QED) system, where atoms coherently interact with photons in a cavity, the eigenstates of the system are the superposition states of atoms and cavity photons, the so-called dressed states of atoms. When two cavities are connected by an optical fiber with negligible loss, the coherent coupling between the cavities gives rise to photonic normal modes. One of these normal modes is the fiber-dark mode, in which photons are delocalized in the two distant cavities. Here we demonstrate the setting of coupled-cavities QED, where two nanofiber cavity-QED systems are coherently connected by a meter-long low-loss channel in an all-fiber fashion. Specifically, we observe dressed states of distant atoms with delocalized photons of the fiber-dark normal mode. Our system will provide a platform for the study of delocalized atomic and photonic states, photonic many-body physics, and distributed quantum computation. The coherent dynamics of coupled atoms that interact with a common mode is different from that of independent atoms. Here the authors demonstrate the delocalization of excited states of atoms and photons using two ensembles of cold Cs atoms in cavities connected with meter long optical fiber.
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9
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Abstract
Experiments and numerical simulations are described that develop quantitative understanding of atomic motion near the surfaces of nanoscopic photonic crystal waveguides (PCWs). Ultracold atoms are delivered from a moving optical lattice into the PCW. Synchronous with the moving lattice, transmission spectra for a guided-mode probe field are recorded as functions of lattice transport time and frequency detuning of the probe beam. By way of measurements such as these, we have been able to validate quantitatively our numerical simulations, which are based upon detailed understanding of atomic trajectories that pass around and through nanoscopic regions of the PCW under the influence of optical and surface forces. The resolution for mapping atomic motion is roughly 50 nm in space and 100 ns in time. By introducing auxiliary guided-mode (GM) fields that provide spatially varying AC Stark shifts, we have, to some degree, begun to control atomic trajectories, such as to enhance the flux into the central vacuum gap of the PCW at predetermined times and with known AC Stark shifts. Applications of these capabilities include enabling high fractional filling of optical trap sites within PCWs, calibration of optical fields within PCWs, and utilization of the time-dependent, optically dense atomic medium for novel nonlinear optical experiments.
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10
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Huang X, Zeuthen E, Vasilyev DV, He Q, Hammerer K, Polzik ES. Unconditional Steady-State Entanglement in Macroscopic Hybrid Systems by Coherent Noise Cancellation. Phys Rev Lett 2018; 121:103602. [PMID: 30240274 DOI: 10.1103/physrevlett.121.103602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Indexed: 06/08/2023]
Abstract
The generation of entanglement between disparate physical objects is a key ingredient in the field of quantum technologies, since they can have different functionalities in a quantum network. Here we propose and analyze a generic approach to steady-state entanglement generation between two oscillators with different temperatures and decoherence properties coupled in cascade to a common unidirectional light field. The scheme is based on a combination of coherent noise cancellation and dynamical cooling techniques for two oscillators with effective masses of opposite signs, such as quasispin and motional degrees of freedom, respectively. The interference effect provided by the cascaded setup can be tuned to implement additional noise cancellation leading to improved entanglement even in the presence of a hot thermal environment. The unconditional entanglement generation is advantageous since it provides a ready-to-use quantum resource. Remarkably, by comparing to the conditional entanglement achievable in the dynamically stable regime, we find our unconditional scheme to deliver a virtually identical performance when operated optimally.
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Affiliation(s)
- Xinyao Huang
- State Key Laboratory of Mesoscopic Physics, School of Physics, Peking University, Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Emil Zeuthen
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Denis V Vasilyev
- Center for Quantum Physics, Faculty of Mathematics, Computer Science and Physics, University of Innsbruck, A-6020 Innsbruck, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
| | - Qiongyi He
- State Key Laboratory of Mesoscopic Physics, School of Physics, Peking University, Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Klemens Hammerer
- Institute for Theoretical Physics and Institute for Gravitational Physics (Albert Einstein Institute), Leibniz Universität Hannover, Callinstraße 38, 30167 Hannover, Germany
| | - Eugene S Polzik
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
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11
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Iakoupov I, Borregaard J, Sørensen AS. Controlled-phase Gate for Photons Based on Stationary Light. Phys Rev Lett 2018; 120:010502. [PMID: 29350945 DOI: 10.1103/physrevlett.120.010502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 10/31/2017] [Indexed: 06/07/2023]
Abstract
We propose a method to induce strong effective interactions between photons mediated by an atomic ensemble. To achieve this, we use the so-called stationary light effect to enhance the interaction. Regardless of the single-atom coupling to light, the interaction strength between the photons can be enhanced by increasing the total number of atoms. For sufficiently many atoms, the setup can be viable as a controlled-phase gate for photons. We derive analytical expressions for the fidelities for two modes of gate operation: deterministic and heralded conditioned on the presence of two photons at the output.
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Affiliation(s)
- Ivan Iakoupov
- The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
| | - Johannes Borregaard
- The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Anders S Sørensen
- The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
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12
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Østfeldt C, Béguin JBS, Pedersen FT, Polzik ES, Müller JH, Appel J. Dipole force free optical control and cooling of nanofiber trapped atoms. Opt Lett 2017; 42:4315-4318. [PMID: 29088152 DOI: 10.1364/ol.42.004315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/18/2017] [Indexed: 06/07/2023]
Abstract
The evanescent field surrounding nanoscale optical waveguides offers an efficient interface between light and mesoscopic ensembles of neutral atoms. However, the thermal motion of trapped atoms, combined with the strong radial gradients of the guided light, leads to a time-modulated coupling between atoms and the light mode, thus giving rise to additional noise and motional dephasing of collective states. Here, we present a dipole force free scheme for coupling of the radial motional states, utilizing the strong intensity gradient of the guided mode and demonstrate all-optical coupling of the cesium hyperfine ground states and motional sideband transitions. We utilize this to prolong the trap lifetime of an atomic ensemble by Raman sideband cooling of the radial motion which, to the best of our knowledge, has not been demonstrated in nano-optical structures previously. This Letter points towards full and independent control of internal and external atomic degrees of freedom using guided light modes only.
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13
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González-Tudela A, Cirac JI. Quantum Emitters in Two-Dimensional Structured Reservoirs in the Nonperturbative Regime. Phys Rev Lett 2017; 119:143602. [PMID: 29053297 DOI: 10.1103/physrevlett.119.143602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Indexed: 06/07/2023]
Abstract
We show that the coupling of quantum emitters to a two-dimensional reservoir with a simple band structure gives rise to exotic quantum dynamics with no analogue in other scenarios and which cannot be captured by standard perturbative treatments. In particular, for a single quantum emitter with its transition frequency in the middle of the band, we predict an exponential relaxation at a rate different from that predicted by Fermi's golden rule, followed by overdamped oscillations and slow relaxation decay dynamics. This is accompanied by directional emission into the reservoir. This directionality leads to a modification of the emission rate for few emitters and even perfect subradiance, i.e., suppression of spontaneous emission, for four quantum emitters.
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Affiliation(s)
- A González-Tudela
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - J I Cirac
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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14
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Solano P, Fatemi FK, Orozco LA, Rolston SL. Dynamics of trapped atoms around an optical nanofiber probed through polarimetry. Opt Lett 2017; 42:2283-2286. [PMID: 28614332 DOI: 10.1364/ol.42.002283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/14/2017] [Indexed: 06/07/2023]
Abstract
The evanescent field outside an optical nanofiber (ONF) can create optical traps for neutral atoms. We present a non-destructive method to characterize such trapping potentials. An off-resonance linearly polarized probe beam that propagates through the ONF experiences a slow axis of polarization produced by trapped atoms on opposite sides along the ONF. The transverse atomic motion is imprinted onto the probe polarization through the changing atomic index of refraction. By applying a transient impulse, we measure a time-dependent polarization rotation of the probe beam that provides both a rapid and non-destructive measurement of the optical trapping frequencies.
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15
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González-Tudela A, Paulisch V, Kimble HJ, Cirac JI. Efficient Multiphoton Generation in Waveguide Quantum Electrodynamics. Phys Rev Lett 2017; 118:213601. [PMID: 28598655 DOI: 10.1103/physrevlett.118.213601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Indexed: 06/07/2023]
Abstract
Engineering quantum states of light is at the basis of many quantum technologies such as quantum cryptography, teleportation, or metrology among others. Though, single photons can be generated in many scenarios, the efficient and reliable generation of complex single-mode multiphoton states is still a long-standing goal in the field, as current methods either suffer from low fidelities or small probabilities. Here we discuss several protocols which harness the strong and long-range atomic interactions induced by waveguide QED to efficiently load excitations in a collection of atoms, which can then be triggered to produce the desired multiphoton state. In order to boost the success probability and fidelity of each excitation process, atoms are used to both generate the excitations in the rest, as well as to herald the successful generation. Furthermore, to overcome the exponential scaling of the probability of success with the number of excitations, we design a protocol to merge excitations that are present in different internal atomic levels with a polynomial scaling.
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Affiliation(s)
- A González-Tudela
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - V Paulisch
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - H J Kimble
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Straße 1, 85748 Garching, Germany
- Norman Bridge Laboratory of Physics 12-33, California Institute of Technology, Pasadena, CA 91125, USA
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA
| | - J I Cirac
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Straße 1, 85748 Garching, Germany
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16
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Colangelo G, Ciurana FM, Bianchet LC, Sewell RJ, Mitchell MW. Simultaneous tracking of spin angle and amplitude beyond classical limits. Nature 2017; 543:525-528. [PMID: 28332519 PMCID: PMC5407441 DOI: 10.1038/nature21434] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 01/19/2017] [Indexed: 11/09/2022]
Abstract
Measurement of spin precession is central to extreme sensing in physics, geophysics, chemistry, nanotechnology and neuroscience, and underlies magnetic resonance spectroscopy. Because there is no spin-angle operator, any measurement of spin precession is necessarily indirect, for example, it may be inferred from spin projectors at different times. Such projectors do not commute, and so quantum measurement back-action-the random change in a quantum state due to measurement-necessarily enters the spin measurement record, introducing errors and limiting sensitivity. Here we show that this disturbance in the spin projector can be reduced below N1/2-the classical limit for N spins-by directing the quantum measurement back-action almost entirely into an unmeasured spin component. This generates a planar squeezed state that, because spins obey non-Heisenberg uncertainty relations, enables simultaneous precise knowledge of spin angle and spin amplitude. We use high-dynamic-range optical quantum non-demolition measurements applied to a precessing magnetic spin ensemble to demonstrate spin tracking with steady-state angular sensitivity 2.9 decibels below the standard quantum limit, simultaneously with amplitude sensitivity 7.0 decibels below the Poissonian variance. The standard quantum limit and Poissonian variance indicate the best possible sensitivity with independent particles. Our method surpasses these limits in non-commuting observables, enabling orders-of-magnitude improvements in sensitivity for state-of-the-art sensing and spectroscopy.
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Affiliation(s)
- Giorgio Colangelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Ferran Martin Ciurana
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Lorena C. Bianchet
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Robert J. Sewell
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Morgan W. Mitchell
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA – Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona, Spain
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17
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Madsen LS, Baker C, Rubinsztein-Dunlop H, Bowen WP. Nondestructive Profilometry of Optical Nanofibers. Nano Lett 2016; 16:7333-7337. [PMID: 27960530 DOI: 10.1021/acs.nanolett.6b02460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Single-mode optical nanofibers are a central component of a broad range of applications and emerging technologies. Their fabrication has been extensively studied over the past decade, but imaging of the final submicrometer products has been restricted to destructive or low-precision techniques. Here, we demonstrate an optical scattering-based scanning method that uses a probe nanofiber to locally scatter the evanescent field of a sample nanofibre. The method does not damage the sample nanofiber and is easily implemented by only using the same equipment as in a standard fiber-puller setup. We demonstrate the subnanometer radial resolution at video rates (0.7 nm in 10 ms) on single mode nanofibers, allowing for a complete high-precision profile to be obtained within minutes of fabrication. The method thus enables nondestructive, fast, and precise characterization of optical nanofibers, with applications ranging from optical sensors and cold atom traps to nonlinear optics.
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Affiliation(s)
- Lars S Madsen
- Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland , Saint Lucia, Brisbane, Queensland 4072, Australia
| | - Christopher Baker
- Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland , Saint Lucia, Brisbane, Queensland 4072, Australia
| | - Halina Rubinsztein-Dunlop
- Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland , Saint Lucia, Brisbane, Queensland 4072, Australia
| | - Warwick P Bowen
- Centre for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland , Saint Lucia, Brisbane, Queensland 4072, Australia
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18
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Sørensen HL, Béguin JB, Kluge KW, Iakoupov I, Sørensen AS, Müller JH, Polzik ES, Appel J. Coherent Backscattering of Light Off One-Dimensional Atomic Strings. Phys Rev Lett 2016; 117:133604. [PMID: 27715084 DOI: 10.1103/physrevlett.117.133604] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Indexed: 06/06/2023]
Abstract
We present the first experimental realization of coherent Bragg scattering off a one-dimensional system-two strings of atoms strongly coupled to a single photonic mode-realized by trapping atoms in the evanescent field of a tapered optical fiber, which also guides the probe light. We report nearly 12% power reflection from strings containing only about 1000 cesium atoms, an enhancement of 2 orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fiber connection between several distant 1D atomic crystals.
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Affiliation(s)
- H L Sørensen
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - J-B Béguin
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - K W Kluge
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - I Iakoupov
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - A S Sørensen
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - J H Müller
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - E S Polzik
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - J Appel
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
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19
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Gajdacz M, Hilliard AJ, Kristensen MA, Pedersen PL, Klempt C, Arlt JJ, Sherson JF. Preparation of Ultracold Atom Clouds at the Shot Noise Level. Phys Rev Lett 2016; 117:073604. [PMID: 27563964 DOI: 10.1103/physrevlett.117.073604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Indexed: 06/06/2023]
Abstract
We prepare number stabilized ultracold atom clouds through the real-time analysis of nondestructive images and the application of feedback. In our experiments, the atom number N∼10^{6} is determined by high precision Faraday imaging with uncertainty ΔN below the shot noise level, i.e., ΔN<sqrt[N]. Based on this measurement, feedback is applied to reduce the atom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level.
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Affiliation(s)
- M Gajdacz
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - A J Hilliard
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - M A Kristensen
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - P L Pedersen
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - C Klempt
- Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover, Germany
| | - J J Arlt
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - J F Sherson
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
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20
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Sadgrove M, Wimberger S, Nic Chormaic S. Quantum coherent tractor beam effect for atoms trapped near a nanowaveguide. Sci Rep 2016; 6:28905. [PMID: 27440516 PMCID: PMC4954976 DOI: 10.1038/srep28905] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/10/2016] [Indexed: 11/25/2022] Open
Abstract
We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold (23)Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tractor beam effect, (ii) an accelerator tractor beam effect, and (iii) a quantum coherent tractor beam effect, all of which can effectively pull atoms along the nanofibre toward the light source. This technique provides a new tool for controlling the motion of particles near nanowaveguides with potential applications in the study of particle transport and binding as well as atom interferometry.
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Affiliation(s)
- Mark Sadgrove
- Research Institute of Electrical Communications, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai-shi Japan
| | - Sandro Wimberger
- Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg, Germany
- Dipartimento di Fisica e Scienze della Terra, Universitádi Parma, Via G. P. Usberti 7/a, 43124 Parma, Italy
- INFN, Sezione di Milano Bicocca, Gruppo Collegato di Parma, Italy
| | - Síle Nic Chormaic
- Light-Matter Interactions Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
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21
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Daly M, Truong VG, Chormaic SN. Evanescent field trapping of nanoparticles using nanostructured ultrathin optical fibers. Opt Express 2016; 24:14470-14482. [PMID: 27410600 DOI: 10.1364/oe.24.014470] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
While conventional optical trapping techniques can trap objects with submicron dimensions, the underlying limits imposed by the diffraction of light generally restrict their use to larger or higher refractive index particles. As the index and diameter decrease, the trapping difficulty rapidly increases; hence, the power requirements for stable trapping become so large as to quickly denature the trapped objects in such diffraction-limited systems. Here, we present an evanescent field-based device capable of confining low index nanoscale particles using modest optical powers as low as 1.2 mW, with additional applications in the field of cold atom trapping. Our experiment uses a nanostructured optical micro-nanofiber to trap 200 nm, low index contrast, fluorescent particles within the structured region, thereby overcoming diffraction limitations. We analyze the trapping potential of this device both experimentally and theoretically, and show how strong optical traps are achieved with low input powers.
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22
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Abstract
We present the experimental measurement of a squeezed vacuum state by means of a bichromatic local oscillator (BLO). A pair of local oscillators at ±5 MHz around the central frequency ω(0) of the fundamental field with equal power are generated by three acousto-optic modulators and phase-locked technology and used as a BLO. The squeezed vacuum light is detected by a phase-sensitive balanced-homodyne detection with a BLO. The baseband signal around ω(0) combined with a broad squeezed field can be detected with the sensitivity below the shot-noise limit, in which the baseband signal is shifted to the vicinity of 5 MHz (the half of the BLO separation). This work has important applications in quantum state measurement and quantum information.
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23
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González-Tudela A, Paulisch V, Chang DE, Kimble HJ, Cirac JI. Deterministic Generation of Arbitrary Photonic States Assisted by Dissipation. Phys Rev Lett 2015; 115:163603. [PMID: 26550876 DOI: 10.1103/physrevlett.115.163603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Indexed: 06/05/2023]
Abstract
A scheme to utilize atomlike emitters coupled to nanophotonic waveguides is proposed for the generation of many-body entangled states and for the reversible mapping of these states of matter to photonic states of an optical pulse in the waveguide. Our protocol makes use of decoherence-free subspaces (DFSs) for the atomic emitters with coherent evolution within the DFSs enforced by strong dissipative coupling to the waveguide. By switching from subradiant to superradiant states, entangled atomic states are mapped to photonic states with high fidelity. An implementation using ultracold atoms coupled to a photonic crystal waveguide is discussed.
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Affiliation(s)
- A González-Tudela
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - V Paulisch
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - D E Chang
- ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain
| | - H J Kimble
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
- Norman Bridge Laboratory of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - J I Cirac
- Max-Planck-Institut für Quantenoptik Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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24
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Abstract
We demonstrate an all-fiber cavity quantum electrodynamics system with a trapped single atom in the strong coupling regime. We use a nanofiber Fabry-Perot cavity, that is, an optical nanofiber sandwiched by two fiber-Bragg-grating mirrors. Measurements of the cavity transmission spectrum with a single atom in a state-insensitive nanofiber trap clearly reveal the vacuum Rabi splitting.
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Affiliation(s)
- Shinya Kato
- Department of Applied Physics, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Takao Aoki
- Department of Applied Physics, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
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