1
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Bosco S, Geyer S, Camenzind LC, Eggli RS, Fuhrer A, Warburton RJ, Zumbühl DM, Egues JC, Kuhlmann AV, Loss D. Phase-Driving Hole Spin Qubits. Phys Rev Lett 2023; 131:197001. [PMID: 38000439 DOI: 10.1103/physrevlett.131.197001] [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: 03/18/2023] [Accepted: 10/03/2023] [Indexed: 11/26/2023]
Abstract
The spin-orbit interaction in spin qubits enables spin-flip transitions, resulting in Rabi oscillations when an external microwave field is resonant with the qubit frequency. Here, we introduce an alternative driving mechanism mediated by the strong spin-orbit interactions in hole spin qubits, where a far-detuned oscillating field couples to the qubit phase. Phase-driving at radio frequencies, orders of magnitude slower than the microwave qubit frequency, induces highly nontrivial spin dynamics, violating the Rabi resonance condition. By using a qubit integrated in a silicon fin field-effect transistor, we demonstrate a controllable suppression of resonant Rabi oscillations and their revivals at tunable sidebands. These sidebands enable alternative qubit control schemes using global fields and local far-detuned pulses, facilitating the design of dense large-scale qubit architectures with local qubit addressability. Phase-driving also decouples Rabi oscillations from noise, an effect due to a gapped Floquet spectrum and can enable Floquet engineering high-fidelity gates in future quantum processors.
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Affiliation(s)
- Stefano Bosco
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Simon Geyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Leon C Camenzind
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Rafael S Eggli
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Andreas Fuhrer
- IBM Research Europe-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Dominik M Zumbühl
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - J Carlos Egues
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, São Paulo, Brazil
| | - Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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2
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Antoniadis NO, Hogg MR, Stehl WF, Javadi A, Tomm N, Schott R, Valentin SR, Wieck AD, Ludwig A, Warburton RJ. Cavity-enhanced single-shot readout of a quantum dot spin within 3 nanoseconds. Nat Commun 2023; 14:3977. [PMID: 37407552 DOI: 10.1038/s41467-023-39568-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023] Open
Abstract
Rapid, high-fidelity single-shot readout of quantum states is a ubiquitous requirement in quantum information technologies. For emitters with a spin-preserving optical transition, spin readout can be achieved by driving the transition with a laser and detecting the emitted photons. The speed and fidelity of this approach is typically limited by low photon collection rates and measurement back-action. Here we use an open microcavity to enhance the optical readout signal from a semiconductor quantum dot spin state, largely overcoming these limitations. We achieve single-shot readout of an electron spin in only 3 nanoseconds with a fidelity of (95.2 ± 0.7)%, and observe quantum jumps using repeated single-shot measurements. Owing to the speed of our readout, errors resulting from measurement-induced back-action have minimal impact. Our work reduces the spin readout-time well below both the achievable spin relaxation and dephasing times in semiconductor quantum dots, opening up new possibilities for their use in quantum technologies.
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Affiliation(s)
- Nadia O Antoniadis
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Mark R Hogg
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
| | - Willy F Stehl
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Alisa Javadi
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
- School of Electrical and Computer Engineering, Department of Physics and Astronomy, The University of Oklahoma, 110 West Boyd Street, Norman, OK, 73019, USA
| | - Natasha Tomm
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Rüdiger Schott
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - Sascha R Valentin
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
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3
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de Kruijf M, Geyer S, Berger T, Mergenthaler M, Braakman F, Warburton RJ, Kuhlmann AV. A compact and versatile cryogenic probe station for quantum device testing. Rev Sci Instrum 2023; 94:2891442. [PMID: 37204282 DOI: 10.1063/5.0139825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 05/01/2023] [Indexed: 05/20/2023]
Abstract
Fast feedback from cryogenic electrical characterization measurements is key for the development of scalable quantum computing technology. At room temperature, high-throughput device testing is accomplished with a probe-based solution, where electrical probes are repeatedly positioned onto devices for acquiring statistical data. In this work, we present a probe station that can be operated from room temperature down to below 2 K. Its small size makes it compatible with standard cryogenic measurement setups with a magnet. A large variety of electronic devices can be tested. Here, we demonstrate the performance of the prober by characterizing silicon fin field-effect transistors as a host for quantum dot spin qubits. Such a tool can massively accelerate the design-fabrication-measurement cycle and provide important feedback for process optimization toward building scalable quantum circuits.
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Affiliation(s)
- Mathieu de Kruijf
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Simon Geyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Toni Berger
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | | | - Floris Braakman
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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4
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Tomm N, Mahmoodian S, Antoniadis NO, Schott R, Valentin SR, Wieck AD, Ludwig A, Javadi A, Warburton RJ. Photon bound state dynamics from a single artificial atom. Nat Phys 2023; 19:857-862. [PMID: 37323806 PMCID: PMC10264240 DOI: 10.1038/s41567-023-01997-6] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 02/20/2023] [Indexed: 06/17/2023]
Abstract
The interaction between photons and a single two-level atom constitutes a fundamental paradigm in quantum physics. The nonlinearity provided by the atom leads to a strong dependence of the light-matter interface on the number of photons interacting with the two-level system within its emission lifetime. This nonlinearity unveils strongly correlated quasiparticles known as photon bound states, giving rise to key physical processes such as stimulated emission and soliton propagation. Although signatures consistent with the existence of photon bound states have been measured in strongly interacting Rydberg gases, their hallmark excitation-number-dependent dispersion and propagation velocity have not yet been observed. Here we report the direct observation of a photon-number-dependent time delay in the scattering off a single artificial atom-a semiconductor quantum dot coupled to an optical cavity. By scattering a weak coherent pulse off the cavity-quantum electrodynamics system and measuring the time-dependent output power and correlation functions, we show that single photons and two- and three-photon bound states incur different time delays, becoming shorter for higher photon numbers. This reduced time delay is a fingerprint of stimulated emission, where the arrival of two photons within the lifetime of an emitter causes one photon to stimulate the emission of another.
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Affiliation(s)
- Natasha Tomm
- Department of Physics, University of Basel, Basel, Switzerland
| | - Sahand Mahmoodian
- Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, New South Wales Australia
- Institute for Theoretical Physics, Institute for Gravitational Physics (Albert Einstein Institute), Leibniz University Hannover, Hannover, Germany
| | | | - Rüdiger Schott
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Sascha R. Valentin
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Andreas D. Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Alisa Javadi
- Department of Physics, University of Basel, Basel, Switzerland
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5
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Sponfeldner L, Leisgang N, Shree S, Paradisanos I, Watanabe K, Taniguchi T, Robert C, Lagarde D, Balocchi A, Marie X, Gerber IC, Urbaszek B, Warburton RJ. Capacitively and Inductively Coupled Excitons in Bilayer MoS_{2}. Phys Rev Lett 2022; 129:107401. [PMID: 36112433 DOI: 10.1103/physrevlett.129.107401] [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: 08/06/2021] [Revised: 01/21/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
The coupling of intralayer A and B excitons and interlayer excitons (IE) is studied in a two-dimensional semiconductor, homobilayer MoS_{2}. It is shown that the measured optical susceptibility reveals both the magnitude and the phase of the coupling constants. The IE and B excitons couple via a 0-phase (capacitive) coupling; the IE and A excitons couple via a π-phase (inductive) coupling. The IE-B and IE-A coupling mechanisms are interpreted as hole tunneling and electron-hole exchange, respectively. The couplings imply that even in a monolayer, the A and B excitons have mixed spin states. Using the IE as a sensor, the A-B intravalley exchange coupling is determined. Finally, we realize a bright and highly tunable lowest-energy momentum-direct exciton at high electric fields.
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Affiliation(s)
- Lukas Sponfeldner
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Nadine Leisgang
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Shivangi Shree
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Ioannis Paradisanos
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Delphine Lagarde
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Andrea Balocchi
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Iann C Gerber
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Bernhard Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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6
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Zhai L, Nguyen GN, Spinnler C, Ritzmann J, Löbl MC, Wieck AD, Ludwig A, Javadi A, Warburton RJ. Quantum interference of identical photons from remote GaAs quantum dots. Nat Nanotechnol 2022; 17:829-833. [PMID: 35589820 DOI: 10.1038/s41565-022-01131-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/01/2022] [Indexed: 06/15/2023]
Abstract
Photonic quantum technology provides a viable route to quantum communication1,2, quantum simulation3 and quantum information processing4. Recent progress has seen the realization of boson sampling using 20 single photons3 and quantum key distribution over hundreds of kilometres2. Scaling the complexity requires architectures containing multiple photon sources, photon counters and a large number of indistinguishable single photons. Semiconductor quantum dots are bright and fast sources of coherent single photons5-9. For applications, a roadblock is the poor quantum coherence on interfering single photons created by independent quantum dots10,11. Here we demonstrate two-photon interference with near-unity visibility (93.0 ± 0.8)% using photons from two completely separate GaAs quantum dots. The experiment retains all the emission into the zero phonon line-only the weak phonon sideband is rejected; temporal post-selection is not employed. By exploiting quantum interference, we demonstrate a photonic controlled-not circuit and an entanglement with fidelity of (85.0 ± 1.0)% between photons of different origins. The two-photon interference visibility is high enough that the entanglement fidelity is well above the classical threshold. The high mutual coherence of the photons stems from high-quality materials, diode structure and relatively large quantum dot size. Our results establish a platform-GaAs quantum dots-for creating coherent single photons in a scalable way.
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Affiliation(s)
- Liang Zhai
- Department of Physics, University of Basel, Basel, Switzerland.
| | - Giang N Nguyen
- Department of Physics, University of Basel, Basel, Switzerland
| | | | - Julian Ritzmann
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Matthias C Löbl
- Department of Physics, University of Basel, Basel, Switzerland
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Alisa Javadi
- Department of Physics, University of Basel, Basel, Switzerland
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7
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Babin HG, Ritzmann J, Bart N, Schmidt M, Kruck T, Zhai L, Löbl MC, Nguyen GN, Spinnler C, Ranasinghe L, Warburton RJ, Heyn C, Wieck AD, Ludwig A. Charge Tunable GaAs Quantum Dots in a Photonic n-i-p Diode. Nanomaterials (Basel) 2021; 11:2703. [PMID: 34685139 PMCID: PMC8537184 DOI: 10.3390/nano11102703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 12/03/2022]
Abstract
In this submission, we discuss the growth of charge-controllable GaAs quantum dots embedded in an n-i-p diode structure, from the perspective of a molecular beam epitaxy grower. The QDs show no blinking and narrow linewidths. We show that the parameters used led to a bimodal growth mode of QDs resulting from low arsenic surface coverage. We identify one of the modes as that showing good properties found in previous work. As the morphology of the fabricated QDs does not hint at outstanding properties, we attribute the good performance of this sample to the low impurity levels in the matrix material and the ability of n- and p-doped contact regions to stabilize the charge state. We present the challenges met in characterizing the sample with ensemble photoluminescence spectroscopy caused by the photonic structure used. We show two straightforward methods to overcome this hurdle and gain insight into QD emission properties.
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Affiliation(s)
- Hans Georg Babin
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
| | - Julian Ritzmann
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
| | - Nikolai Bart
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
| | - Marcel Schmidt
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
| | - Timo Kruck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
| | - Liang Zhai
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland; (L.Z.); (M.C.L.); (G.N.N.); (C.S.); (R.J.W.)
| | - Matthias C. Löbl
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland; (L.Z.); (M.C.L.); (G.N.N.); (C.S.); (R.J.W.)
| | - Giang N. Nguyen
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland; (L.Z.); (M.C.L.); (G.N.N.); (C.S.); (R.J.W.)
| | - Clemens Spinnler
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland; (L.Z.); (M.C.L.); (G.N.N.); (C.S.); (R.J.W.)
| | - Leonardo Ranasinghe
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, DE-22761 Hamburg, Germany; (L.R.); (C.H.)
| | - Richard J. Warburton
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland; (L.Z.); (M.C.L.); (G.N.N.); (C.S.); (R.J.W.)
| | - Christian Heyn
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, DE-22761 Hamburg, Germany; (L.R.); (C.H.)
| | - Andreas D. Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, DE-44801 Bochum, Germany; (J.R.); (N.B.); (M.S.); (T.K.); (A.D.W.); (A.L.)
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8
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Appel MH, Tiranov A, Javadi A, Löbl MC, Wang Y, Scholz S, Wieck AD, Ludwig A, Warburton RJ, Lodahl P. Coherent Spin-Photon Interface with Waveguide Induced Cycling Transitions. Phys Rev Lett 2021; 126:013602. [PMID: 33480775 DOI: 10.1103/physrevlett.126.013602] [Citation(s) in RCA: 2] [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: 06/27/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Solid-state quantum dots are promising candidates for efficient light-matter interfaces connecting internal spin degrees of freedom to the states of emitted photons. However, selection rules prevent the combination of efficient spin control and optical cyclicity in this platform. By utilizing a photonic crystal waveguide we here experimentally demonstrate optical cyclicity up to ≈15 through photonic state engineering while achieving high fidelity spin initialization and coherent optical spin control. These capabilities pave the way towards scalable multiphoton entanglement generation and on-chip spin-photon gates.
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Affiliation(s)
- Martin Hayhurst Appel
- Center for Hybrid Quantum Networks (Hy-Q), The Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Alexey Tiranov
- Center for Hybrid Quantum Networks (Hy-Q), The Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Alisa Javadi
- Department of Physics, University of Basel, Klingelbergstraße 82, CH-4056 Basel, Switzerland
| | - Matthias C Löbl
- Department of Physics, University of Basel, Klingelbergstraße 82, CH-4056 Basel, Switzerland
| | - Ying Wang
- Center for Hybrid Quantum Networks (Hy-Q), The Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Sven Scholz
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstraße 82, CH-4056 Basel, Switzerland
| | - Peter Lodahl
- Center for Hybrid Quantum Networks (Hy-Q), The Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
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9
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Leisgang N, Shree S, Paradisanos I, Sponfeldner L, Robert C, Lagarde D, Balocchi A, Watanabe K, Taniguchi T, Marie X, Warburton RJ, Gerber IC, Urbaszek B. Giant Stark splitting of an exciton in bilayer MoS 2. Nat Nanotechnol 2020; 15:901-907. [PMID: 32778806 DOI: 10.1038/s41565-020-0750-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Transition metal dichalcogenides (TMDs) constitute a versatile platform for atomically thin optoelectronics devices and spin-valley memory applications. In monolayer TMDs the optical absorption is strong, but the transition energy cannot be tuned as the neutral exciton has essentially no out-of-plane static electric dipole1,2. In contrast, interlayer exciton transitions in heterobilayers are widely tunable in applied electric fields, but their coupling to light is substantially reduced. In this work, we show tuning over 120 meV of interlayer excitons with a high oscillator strength in bilayer MoS2 due to the quantum-confined Stark effect3. We optically probed the interaction between intra- and interlayer excitons as they were energetically tuned into resonance. Interlayer excitons interact strongly with intralayer B excitons, as demonstrated by a clear avoided crossing, whereas the interaction with intralayer A excitons is substantially weaker. Our observations are supported by density functional theory (DFT) calculations, which include excitonic effects. In MoS2 trilayers, our experiments uncovered two types of interlayer excitons with and without in-built electric dipoles. Highly tunable excitonic transitions with large in-built dipoles and oscillator strengths will result in strong exciton-exciton interactions and therefore hold great promise for non-linear optics with polaritons.
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Affiliation(s)
- Nadine Leisgang
- Department of Physics, University of Basel, Basel, Switzerland
| | - Shivangi Shree
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | | | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | - Andrea Balocchi
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
| | - Takashi Taniguchi
- International Center for Materials Anorthite, National Institute for Materials Science, Ibaraki, Japan
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | - Iann C Gerber
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
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10
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Zhai L, Löbl MC, Nguyen GN, Ritzmann J, Javadi A, Spinnler C, Wieck AD, Ludwig A, Warburton RJ. Low-noise GaAs quantum dots for quantum photonics. Nat Commun 2020; 11:4745. [PMID: 32958795 PMCID: PMC7506537 DOI: 10.1038/s41467-020-18625-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [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: 03/25/2020] [Accepted: 09/03/2020] [Indexed: 11/18/2022] Open
Abstract
Quantum dots are both excellent single-photon sources and hosts for single spins. This combination enables the deterministic generation of Raman-photons—bandwidth-matched to an atomic quantum-memory—and the generation of photon cluster states, a resource in quantum communication and measurement-based quantum computing. GaAs quantum dots in AlGaAs can be matched in frequency to a rubidium-based photon memory, and have potentially improved electron spin coherence compared to the widely used InGaAs quantum dots. However, their charge stability and optical linewidths are typically much worse than for their InGaAs counterparts. Here, we embed GaAs quantum dots into an n-i-p-diode specially designed for low-temperature operation. We demonstrate ultra-low noise behaviour: charge control via Coulomb blockade, close-to lifetime-limited linewidths, and no blinking. We observe high-fidelity optical electron-spin initialisation and long electron-spin lifetimes for these quantum dots. Our work establishes a materials platform for low-noise quantum photonics close to the red part of the spectrum. GaAs quantum dots emitting at the near-red part of the spectrum usually suffers from excess charge-noise. With a careful design of a n-i-p-diode structure hosting GaAs quantum dots, the authors demonstrate ultralow-noise behaviour and high-fidelity spin initialisation close to rubidium wavelengths.
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Affiliation(s)
- Liang Zhai
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
| | - Matthias C Löbl
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Giang N Nguyen
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.,Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, DE-44780, Bochum, Germany
| | - Julian Ritzmann
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, DE-44780, Bochum, Germany
| | - Alisa Javadi
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Clemens Spinnler
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, DE-44780, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, DE-44780, Bochum, Germany
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
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11
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Uppu R, Eriksen HT, Thyrrestrup H, Uğurlu AD, Wang Y, Scholz S, Wieck AD, Ludwig A, Löbl MC, Warburton RJ, Lodahl P, Midolo L. On-chip deterministic operation of quantum dots in dual-mode waveguides for a plug-and-play single-photon source. Nat Commun 2020; 11:3782. [PMID: 32728025 PMCID: PMC7391626 DOI: 10.1038/s41467-020-17603-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [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: 04/25/2020] [Accepted: 07/09/2020] [Indexed: 12/03/2022] Open
Abstract
A deterministic source of coherent single photons is an enabling device for quantum information processing. Quantum dots in nanophotonic structures have been employed as excellent sources of single photons with the promise of scaling up towards multiple photons and emitters. It remains a challenge to implement deterministic resonant optical excitation of the quantum dot required for generating coherent single photons, since residual light from the excitation laser should be suppressed without compromising source efficiency and scalability. Here, we present a planar nanophotonic circuit that enables deterministic pulsed resonant excitation of quantum dots using two orthogonal waveguide modes for separating the laser and the emitted photons. We report a coherent and stable single-photon source that simultaneously achieves high-purity (g(2)(0) = 0.020 ± 0.005), high-indistinguishability (V = 96 ± 2%), and >80% coupling efficiency into the waveguide. Such ‘plug-and-play’ single-photon source can be integrated with on-chip optical networks implementing photonic quantum processors. Resonantly-excited quantum-dot-based single photon sources feature very high purity, but also limited efficiency due to the need to suppress the residual pump. Here, the authors demonstrate a workaround, performing optical pumping and signal collection in two orthogonal modes inside a nanophotonic circuit.
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Affiliation(s)
- Ravitej Uppu
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark.
| | - Hans T Eriksen
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark
| | - Henri Thyrrestrup
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark
| | - Aslı D Uğurlu
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark
| | - Ying Wang
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark
| | - Sven Scholz
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Matthias C Löbl
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056, Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056, Basel, Switzerland
| | - Peter Lodahl
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark
| | - Leonardo Midolo
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark.
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12
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Löbl MC, Spinnler C, Javadi A, Zhai L, Nguyen GN, Ritzmann J, Midolo L, Lodahl P, Wieck AD, Ludwig A, Warburton RJ. Radiative Auger process in the single-photon limit. Nat Nanotechnol 2020; 15:558-562. [PMID: 32541943 DOI: 10.1038/s41565-020-0697-2] [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: 12/10/2019] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
In a multi-electron atom, an excited electron can decay by emitting a photon. Typically, the leftover electrons are in their ground state. In a radiative Auger process, the leftover electrons are in an excited state and a redshifted photon is created1-4. In a semiconductor quantum dot, radiative Auger is predicted for charged excitons5. Here we report the observation of radiative Auger on trions in single quantum dots. For a trion, a photon is created on electron-hole recombination, leaving behind a single electron. The radiative Auger process promotes this additional (Auger) electron to a higher shell of the quantum dot. We show that the radiative Auger effect is a powerful probe of this single electron: the energy separations between the resonance fluorescence and the radiative Auger emission directly measure the single-particle splittings of the electronic states in the quantum dot with high precision. In semiconductors, these single-particle splittings are otherwise hard to access by optical means as particles are excited typically in pairs, as excitons. After the radiative Auger emission, the Auger carrier relaxes back to the lowest shell. Going beyond the original theoretical proposals, we show how applying quantum optics techniques to the radiative Auger photons gives access to the single-electron dynamics, notably relaxation and tunnelling. This is also hard to access by optical means: even for quasi-resonant p-shell excitation, electron relaxation takes place in the presence of a hole, complicating the relaxation dynamics. The radiative Auger effect can be exploited in other semiconductor nanostructures and quantum emitters in the solid state to determine the energy levels and the dynamics of a single carrier.
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Affiliation(s)
- Matthias C Löbl
- Department of Physics, University of Basel, Basel, Switzerland.
| | | | - Alisa Javadi
- Department of Physics, University of Basel, Basel, Switzerland
| | - Liang Zhai
- Department of Physics, University of Basel, Basel, Switzerland
| | - Giang N Nguyen
- Department of Physics, University of Basel, Basel, Switzerland
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Julian Ritzmann
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Leonardo Midolo
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Peter Lodahl
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
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13
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Paradisanos I, Shree S, George A, Leisgang N, Robert C, Watanabe K, Taniguchi T, Warburton RJ, Turchanin A, Marie X, Gerber IC, Urbaszek B. Controlling interlayer excitons in MoS 2 layers grown by chemical vapor deposition. Nat Commun 2020; 11:2391. [PMID: 32404912 PMCID: PMC7220905 DOI: 10.1038/s41467-020-16023-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/06/2020] [Indexed: 12/18/2022] Open
Abstract
Combining MoS2 monolayers to form multilayers allows to access new functionalities. Deterministic assembly of large area van der Waals structures requires concrete indicators of successful interlayer coupling in bilayers grown by chemical vapor deposition. In this work, we examine the correlation between the stacking order and the interlayer coupling of valence states in both as-grown MoS2 homobilayer samples and in artificially stacked bilayers from monolayers, all grown by chemical vapor deposition. We show that hole delocalization over the bilayer is only allowed in 2H stacking and results in strong interlayer exciton absorption and also in a larger A-B exciton separation as compared to 3R bilayers. Comparing 2H and 3R reflectivity spectra allows to extract an interlayer coupling energy of about t⊥ = 49 meV. Beyond DFT calculations including excitonic effects confirm signatures of efficient interlayer coupling for 2H stacking in agreement with our experiments.
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Affiliation(s)
- Ioannis Paradisanos
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Shivangi Shree
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Antony George
- Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Nadine Leisgang
- Department of Physics, University of Basel, Basel, Switzerland
| | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
| | | | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
- Abbe Centre of Photonics, 07745, Jena, Germany
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Iann C Gerber
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France.
| | - Bernhard Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France.
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14
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Roch JG, Miserev D, Froehlicher G, Leisgang N, Sponfeldner L, Watanabe K, Taniguchi T, Klinovaja J, Loss D, Warburton RJ. First-Order Magnetic Phase Transition of Mobile Electrons in Monolayer MoS_{2}. Phys Rev Lett 2020; 124:187602. [PMID: 32441950 DOI: 10.1103/physrevlett.124.187602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Evidence is presented for a first-order magnetic phase transition in a gated two-dimensional semiconductor, monolayer-MoS_{2}. The phase boundary separates a ferromagnetic phase at low electron density and a paramagnetic phase at high electron density. Abrupt changes in the optical response signal an abrupt change in the magnetism. The magnetic order is thereby controlled via the voltage applied to the gate electrode of the device. Accompanying the change in magnetism is a large change in the electron effective mass.
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Affiliation(s)
- Jonas G Roch
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Dmitry Miserev
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Guillaume Froehlicher
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Nadine Leisgang
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Lukas Sponfeldner
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Kenji Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Jelena Klinovaja
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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15
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Thyrrestrup H, Kiršanskė G, Le Jeannic H, Pregnolato T, Zhai L, Raahauge L, Midolo L, Rotenberg N, Javadi A, Schott R, Wieck AD, Ludwig A, Löbl MC, Söllner I, Warburton RJ, Lodahl P. Quantum Optics with Near-Lifetime-Limited Quantum-Dot Transitions in a Nanophotonic Waveguide. Nano Lett 2018; 18:1801-1806. [PMID: 29494160 DOI: 10.1021/acs.nanolett.7b05016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Establishing a highly efficient photon-emitter interface where the intrinsic linewidth broadening is limited solely by spontaneous emission is a key step in quantum optics. It opens a pathway to coherent light-matter interaction for, e.g., the generation of highly indistinguishable photons, few-photon optical nonlinearities, and photon-emitter quantum gates. However, residual broadening mechanisms are ubiquitous and need to be combated. For solid-state emitters charge and nuclear spin noise are of importance, and the influence of photonic nanostructures on the broadening has not been clarified. We present near-lifetime-limited linewidths for quantum dots embedded in nanophotonic waveguides through a resonant transmission experiment. It is found that the scattering of single photons from the quantum dot can be obtained with an extinction of 66 ± 4%, which is limited by the coupling of the quantum dot to the nanostructure rather than the linewidth broadening. This is obtained by embedding the quantum dot in an electrically contacted nanophotonic membrane. A clear pathway to obtaining even larger single-photon extinction is laid out; i.e., the approach enables a fully deterministic and coherent photon-emitter interface in the solid state that is operated at optical frequencies.
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Affiliation(s)
- Henri Thyrrestrup
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Gabija Kiršanskė
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Hanna Le Jeannic
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Tommaso Pregnolato
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Liang Zhai
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Laust Raahauge
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Leonardo Midolo
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Nir Rotenberg
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Alisa Javadi
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
| | - Rüdiger Schott
- Lehrstuhl für Angewandte Festkörperphysik , Ruhr-Universität Bochum , Universitätsstrasse 150 , D-44780 Bochum , Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik , Ruhr-Universität Bochum , Universitätsstrasse 150 , D-44780 Bochum , Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik , Ruhr-Universität Bochum , Universitätsstrasse 150 , D-44780 Bochum , Germany
| | - Matthias C Löbl
- Department of Physics , University of Basel , Klingelbergstrasse 82 , CH-4056 Basel , Switzerland
| | - Immo Söllner
- Department of Physics , University of Basel , Klingelbergstrasse 82 , CH-4056 Basel , Switzerland
| | - Richard J Warburton
- Department of Physics , University of Basel , Klingelbergstrasse 82 , CH-4056 Basel , Switzerland
| | - Peter Lodahl
- Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17 , DK-2100 Copenhagen , Denmark
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16
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Roch JG, Leisgang N, Froehlicher G, Makk P, Watanabe K, Taniguchi T, Schönenberger C, Warburton RJ. Quantum-Confined Stark Effect in a MoS 2 Monolayer van der Waals Heterostructure. Nano Lett 2018; 18:1070-1074. [PMID: 29378141 DOI: 10.1021/acs.nanolett.7b04553] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The optics of dangling-bond-free van der Waals heterostructures containing transition metal dichalcogenides are dominated by excitons. A crucial property of a confined exciton is the quantum confined Stark effect (QCSE). Here, such a heterostructure is used to probe the QCSE by applying a uniform vertical electric field across a molybdenum disulfide (MoS2) monolayer. The photoluminescence emission energies of the neutral and charged excitons shift quadratically with the applied electric field, provided that the electron density remains constant, demonstrating that the exciton can be polarized. Stark shifts corresponding to about half the homogeneous linewidth were achieved. Neutral and charged exciton polarizabilities of (7.8 ± 1.0) × 10-10 and (6.4 ± 0.9) × 10-10 D m V-1 at relatively low electron density (∼1012 cm-2) have been extracted, respectively. These values are one order of magnitude lower than the previously reported values but in line with theoretical calculations. The methodology presented here is versatile and can be applied to other semiconducting layered materials.
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Affiliation(s)
- Jonas G Roch
- Department of Physics, University of Basel , Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Nadine Leisgang
- Department of Physics, University of Basel , Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Guillaume Froehlicher
- Department of Physics, University of Basel , Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Peter Makk
- Department of Physics, University of Basel , Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Kenji Watanabe
- National Institute for Material Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Material Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Christian Schönenberger
- Department of Physics, University of Basel , Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel , Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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17
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Wolters J, Buser G, Horsley A, Béguin L, Jöckel A, Jahn JP, Warburton RJ, Treutlein P. Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons. Phys Rev Lett 2017; 119:060502. [PMID: 28949634 DOI: 10.1103/physrevlett.119.060502] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 06/07/2023]
Abstract
Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δf=0.66 GHz, the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure η_{e2e}^{50 ns}=3.4(3)% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency η_{int}=17(3)%. Straightforward technological improvements can boost the end-to-end-efficiency to η_{e2e}≈35%; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9×10^{-3} photons is dominated by atomic fluorescence, and for input pulses containing on average μ_{1}=0.27(4) photons, the signal to noise level would be unity.
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Affiliation(s)
- Janik Wolters
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Gianni Buser
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andrew Horsley
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Lucas Béguin
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andreas Jöckel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Jan-Philipp Jahn
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Philipp Treutlein
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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18
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Wüst G, Munsch M, Maier F, Kuhlmann AV, Ludwig A, Wieck AD, Loss D, Poggio M, Warburton RJ. Role of the electron spin in determining the coherence of the nuclear spins in a quantum dot. Nat Nanotechnol 2016; 11:885-889. [PMID: 27428274 DOI: 10.1038/nnano.2016.114] [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] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/23/2016] [Indexed: 06/06/2023]
Abstract
A huge effort is underway to develop semiconductor nanostructures as low-noise qubits. A key source of dephasing for an electron spin qubit in GaAs and in naturally occurring Si is the nuclear spin bath. The electron spin is coupled to each nuclear spin by the hyperfine interaction. The same interaction also couples two remote nuclear spins via a common coupling to the delocalized electron. It has been suggested that this interaction limits both electron and nuclear spin coherence, but experimental proof is lacking. We show that the nuclear spin decoherence time decreases by two orders of magnitude on occupying an empty quantum dot with a single electron, recovering to its original value for two electrons. In the case of one electron, agreement with a model calculation verifies the hypothesis of an electron-mediated nuclear spin-nuclear spin coupling. The results establish a framework to understand the main features of this complex interaction in semiconductor nanostructures.
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Affiliation(s)
- Gunter Wüst
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Mathieu Munsch
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Franziska Maier
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Martino Poggio
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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19
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Prechtel JH, Kuhlmann AV, Houel J, Ludwig A, Valentin SR, Wieck AD, Warburton RJ. Decoupling a hole spin qubit from the nuclear spins. Nat Mater 2016; 15:981-6. [PMID: 27454044 DOI: 10.1038/nmat4704] [Citation(s) in RCA: 5] [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: 04/28/2015] [Accepted: 06/21/2016] [Indexed: 05/14/2023]
Abstract
A huge effort is underway to develop semiconductor nanostructures as low-noise hosts for qubits. The main source of dephasing of an electron spin qubit in a GaAs-based system is the nuclear spin bath. A hole spin may circumvent the nuclear spin noise. In principle, the nuclear spins can be switched off for a pure heavy-hole spin. In practice, it is unknown to what extent this ideal limit can be achieved. A major hindrance is that p-type devices are often far too noisy. We investigate here a single hole spin in an InGaAs quantum dot embedded in a new generation of low-noise p-type device. We measure the hole Zeeman energy in a transverse magnetic field with 10 neV resolution by dark-state spectroscopy as we create a large transverse nuclear spin polarization. The hole hyperfine interaction is highly anisotropic: the transverse coupling is <1% of the longitudinal coupling. For unpolarized, randomly fluctuating nuclei, the ideal heavy-hole limit is achieved down to nanoelectronvolt energies; equivalently dephasing times up to a microsecond. The combination of large and strong optical dipole makes the single hole spin in a GaAs-based device an attractive quantum platform.
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Affiliation(s)
- Jonathan H Prechtel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Julien Houel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
- Institut Lumière Matière (ILM), UMR5306 Université Lyon 1/CNRS, Université de Lyon, 69622 Villeurbanne Cedex, France
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Sascha R Valentin
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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20
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Munsch M, Wüst G, Kuhlmann AV, Xue F, Ludwig A, Reuter D, Wieck AD, Poggio M, Warburton RJ. Manipulation of the nuclear spin ensemble in a quantum dot with chirped magnetic resonance pulses. Nat Nanotechnol 2014; 9:671-675. [PMID: 25150719 DOI: 10.1038/nnano.2014.175] [Citation(s) in RCA: 4] [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: 11/11/2013] [Accepted: 07/16/2014] [Indexed: 06/03/2023]
Abstract
The nuclear spins in nanostructured semiconductors play a central role in quantum applications. The nuclear spins represent a useful resource for generating local magnetic fields but nuclear spin noise represents a major source of dephasing for spin qubits. Controlling the nuclear spins enhances the resource while suppressing the noise. NMR techniques are challenging: the group III and V isotopes have large spins with widely different gyromagnetic ratios; in strained material there are large atom-dependent quadrupole shifts; and nanoscale NMR is hard to detect. We report NMR on 100,000 nuclear spins of a quantum dot using chirped radiofrequency pulses. Following polarization, we demonstrate a reversal of the nuclear spin. We can flip the nuclear spin back and forth a hundred times. We demonstrate that chirped NMR is a powerful way of determining the chemical composition, the initial nuclear spin temperatures and quadrupole frequency distributions for all the main isotopes. The key observation is a plateau in the NMR signal as a function of sweep rate: we achieve inversion at the first quantum transition for all isotopes simultaneously. These experiments represent a generic technique for manipulating nanoscale inhomogeneous nuclear spin ensembles and open the way to probe the coherence of such mesoscopic systems.
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Affiliation(s)
- Mathieu Munsch
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Gunter Wüst
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Fei Xue
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Arne Ludwig
- 1] Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland [2] Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Dirk Reuter
- 1] Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany [2] Department Physik, Universität Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - Martino Poggio
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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21
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Montinaro M, Wüst G, Munsch M, Fontana Y, Russo-Averchi E, Heiss M, Fontcuberta I Morral A, Warburton RJ, Poggio M. Quantum dot opto-mechanics in a fully self-assembled nanowire. Nano Lett 2014; 14:4454-60. [PMID: 25010118 DOI: 10.1021/nl501413t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We show that optically active quantum dots (QDs) embedded in MBE-grown GaAs/AlGaAs core-shell nanowires (NWs) are coupled to the NW mechanical motion. Oscillations of the NW modulate the QD emission energy in a broad range exceeding 14 meV. Furthermore, this opto-mechanical interaction enables the dynamical tuning of two neighboring QDs into resonance, possibly allowing for emitter-emitter coupling. Both the QDs and the coupling mechanism, i.e. material strain, are intrinsic to the NW structure and do not depend on any functionalization or external field. Such systems open up the prospect of using QDs to probe and control the mechanical state of a NW, or conversely of making a quantum nondemolition readout of a QD state through a position measurement.
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Affiliation(s)
- Michele Montinaro
- Department of Physics, University of Basel , Klingelbergstrasse 82, 4056 Basel, Switzerland
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22
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Houel J, Prechtel JH, Kuhlmann AV, Brunner D, Kuklewicz CE, Gerardot BD, Stoltz NG, Petroff PM, Warburton RJ. High resolution coherent population trapping on a single hole spin in a semiconductor quantum dot. Phys Rev Lett 2014; 112:107401. [PMID: 24679326 DOI: 10.1103/physrevlett.112.107401] [Citation(s) in RCA: 3] [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: 07/08/2013] [Indexed: 06/03/2023]
Abstract
We report high resolution coherent population trapping on a single hole spin in a semiconductor quantum dot. The absorption dip signifying the formation of a dark state exhibits an atomic physicslike dip width of just 10 MHz. We observe fluctuations in the absolute frequency of the absorption dip, evidence of very slow spin dephasing. We identify the cause of this process as charge noise by, first, demonstrating that the hole spin g factor in this configuration (in-plane magnetic field) is strongly dependent on the vertical electric field, and second, by characterizing the charge noise through its effects on the optical transition frequency. An important conclusion is that charge noise is an important hole spin dephasing process.
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Affiliation(s)
- Julien Houel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH 4056 Basel, Switzerland and Institut Lumière Matière (ILM), UMR5306 Université Lyon 1/CNRS, Université de Lyon, 69622 Villeurbanne Cedex, France
| | - Jonathan H Prechtel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH 4056 Basel, Switzerland
| | - Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH 4056 Basel, Switzerland
| | - Daniel Brunner
- Instituto de Fisica Interdisciplinar y Sistemas Complejos, IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca E-07122, Spain
| | - Christopher E Kuklewicz
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Brian D Gerardot
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Nick G Stoltz
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Pierre M Petroff
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Richard J Warburton
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH 4056 Basel, Switzerland
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23
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Kuhlmann AV, Houel J, Brunner D, Ludwig A, Reuter D, Wieck AD, Warburton RJ. A dark-field microscope for background-free detection of resonance fluorescence from single semiconductor quantum dots operating in a set-and-forget mode. Rev Sci Instrum 2013; 84:073905. [PMID: 23902082 DOI: 10.1063/1.4813879] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Optically active quantum dots, for instance self-assembled InGaAs quantum dots, are potentially excellent single photon sources. The fidelity of the single photons is much improved using resonant rather than non-resonant excitation. With resonant excitation, the challenge is to distinguish between resonance fluorescence and scattered laser light. We have met this challenge by creating a polarization-based dark-field microscope to measure the resonance fluorescence from a single quantum dot at low temperature. We achieve a suppression of the scattered laser exceeding a factor of 10(7) and background-free detection of resonance fluorescence. The same optical setup operates over the entire quantum dot emission range (920-980 nm) and also in high magnetic fields. The major development is the outstanding long-term stability: once the dark-field point has been established, the microscope operates for days without alignment. The mechanical and optical designs of the microscope are presented, as well as exemplary resonance fluorescence spectroscopy results on individual quantum dots to underline the microscope's excellent performance.
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Affiliation(s)
- Andreas V Kuhlmann
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
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24
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Abstract
Self-assembled quantum dots have excellent photonic properties. For instance, a single quantum dot is a high-brightness, narrow-linewidth source of single photons. Furthermore, the environment of a single quantum dot can be tailored relatively easily using semiconductor heterostructure and post-growth processing techniques, enabling electrical control of the quantum dot charge and control over the photonic modes with which the quantum dot interacts. A single electron or hole trapped inside a quantum dot has spintronics applications. Although the spin dephasing is rather rapid, a single spin can be manipulated using optical techniques on subnanosecond timescales. Optical experiments are also providing new insights into old issues, such as the central spin problem. This Review provides a snapshot of this active field, with some indications for the future. It covers the basic materials and optical properties of single quantum dots, techniques for initializing, manipulating and reading out single spin qubits, and the mechanisms that limit the electron-spin and hole-spin coherence.
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25
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Heiss M, Fontana Y, Gustafsson A, Wüst G, Magen C, O'Regan DD, Luo JW, Ketterer B, Conesa-Boj S, Kuhlmann AV, Houel J, Russo-Averchi E, Morante JR, Cantoni M, Marzari N, Arbiol J, Zunger A, Warburton RJ, Fontcuberta i Morral A. Self-assembled quantum dots in a nanowire system for quantum photonics. Nat Mater 2013; 12:439-44. [PMID: 23377293 DOI: 10.1038/nmat3557] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 12/21/2012] [Indexed: 05/24/2023]
Abstract
Quantum dots embedded within nanowires represent one of the most promising technologies for applications in quantum photonics. Whereas the top-down fabrication of such structures remains a technological challenge, their bottom-up fabrication through self-assembly is a potentially more powerful strategy. However, present approaches often yield quantum dots with large optical linewidths, making reproducibility of their physical properties difficult. We present a versatile quantum-dot-in-nanowire system that reproducibly self-assembles in core-shell GaAs/AlGaAs nanowires. The quantum dots form at the apex of a GaAs/AlGaAs interface, are highly stable, and can be positioned with nanometre precision relative to the nanowire centre. Unusually, their emission is blue-shifted relative to the lowest energy continuum states of the GaAs core. Large-scale electronic structure calculations show that the origin of the optical transitions lies in quantum confinement due to Al-rich barriers. By emitting in the red and self-assembling on silicon substrates, these quantum dots could therefore become building blocks for solid-state lighting devices and third-generation solar cells.
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Affiliation(s)
- M Heiss
- Laboratoire des Matériaux Semiconducteurs, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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26
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Houel J, Kuhlmann AV, Greuter L, Xue F, Poggio M, Gerardot BD, Dalgarno PA, Badolato A, Petroff PM, Ludwig A, Reuter D, Wieck AD, Warburton RJ. Probing single-charge fluctuations at a GaAs/AlAs interface using laser spectroscopy on a nearby InGaAs quantum dot. Phys Rev Lett 2012; 108:107401. [PMID: 22463453 DOI: 10.1103/physrevlett.108.107401] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Indexed: 05/31/2023]
Abstract
We probe local charge fluctuations in a semiconductor via laser spectroscopy on a nearby self-assembled quantum dot. We demonstrate that the quantum dot is sensitive to changes in the local environment at the single-charge level. By controlling the charge state of localized defects, we are able to infer the distance of the defects from the quantum dot with ±5 nm resolution. The results identify and quantify the main source of charge noise in the commonly used optical field-effect devices.
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Affiliation(s)
- J Houel
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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27
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Simon CM, Belhadj T, Chatel B, Amand T, Renucci P, Lemaitre A, Krebs O, Dalgarno PA, Warburton RJ, Marie X, Urbaszek B. Robust quantum dot exciton generation via adiabatic passage with frequency-swept optical pulses. Phys Rev Lett 2011; 106:166801. [PMID: 21599394 DOI: 10.1103/physrevlett.106.166801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 03/09/2011] [Indexed: 05/30/2023]
Abstract
The energy states in semiconductor quantum dots are discrete as in atoms, and quantum states can be coherently controlled with resonant laser pulses. Long coherence times allow the observation of Rabi flopping of a single dipole transition in a solid state device, for which occupancy of the upper state depends sensitively on the dipole moment and the excitation laser power. We report on the robust population inversion in a single quantum dot using an optical technique that exploits rapid adiabatic passage from the ground to an excited state through excitation with laser pulses whose frequency is swept through the resonance. This observation in photoluminescence experiments is made possible by introducing a novel optical detection scheme for the resonant electron hole pair (exciton) generation.
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Affiliation(s)
- C-M Simon
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
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28
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Kloeffel C, Dalgarno PA, Urbaszek B, Gerardot BD, Brunner D, Petroff PM, Loss D, Warburton RJ. Controlling the interaction of electron and nuclear spins in a tunnel-coupled quantum dot. Phys Rev Lett 2011; 106:046802. [PMID: 21405345 DOI: 10.1103/physrevlett.106.046802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Indexed: 05/30/2023]
Abstract
We present a technique for manipulating the nuclear spins and the emission polarization from a single optically active quantum dot. When the quantum dot is tunnel coupled to a Fermi sea, we have discovered a natural cycle in which an electron spin is repeatedly created with resonant optical excitation. The spontaneous emission polarization and the nuclear spin polarization exhibit a bistability. For a σ(+) pump, the emission switches from σ(+) to σ(-) at a particular detuning of the laser. Simultaneously, the nuclear spin polarization switches from positive to negative. Away from the bistability, the nuclear spin polarization can be changed continuously from negative to positive, allowing precise control via the laser wavelength.
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Affiliation(s)
- C Kloeffel
- Department of Physics, University of Basel, Basel, Switzerland
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29
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Dalgarno HIC, Dalgarno PA, Dada AC, Towers CE, Gibson GJ, Parton RM, Davis I, Warburton RJ, Greenaway AH. Nanometric depth resolution from multi-focal images in microscopy. J R Soc Interface 2011; 8:942-51. [PMID: 21247948 PMCID: PMC3104330 DOI: 10.1098/rsif.2010.0508] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [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] [Indexed: 11/12/2022] Open
Abstract
We describe a method for tracking the position of small features in three dimensions from images recorded on a standard microscope with an inexpensive attachment between the microscope and the camera. The depth-measurement accuracy of this method is tested experimentally on a wide-field, inverted microscope and is shown to give approximately 8 nm depth resolution, over a specimen depth of approximately 6 µm, when using a 12-bit charge-coupled device (CCD) camera and very bright but unresolved particles. To assess low-flux limitations a theoretical model is used to derive an analytical expression for the minimum variance bound. The approximations used in the analytical treatment are tested using numerical simulations. It is concluded that approximately 14 nm depth resolution is achievable with flux levels available when tracking fluorescent sources in three dimensions in live-cell biology and that the method is suitable for three-dimensional photo-activated localization microscopy resolution. Sub-nanometre resolution could be achieved with photon-counting techniques at high flux levels.
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Affiliation(s)
- Heather I C Dalgarno
- Physics, SUPA/IIS, School of Engineering and Physical Sciences, Heriot-Watt University, , Edinburgh EH14 4AS, UK
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30
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Dalgarno PA, Dalgarno HIC, Putoud A, Lambert R, Paterson L, Logan DC, Towers DP, Warburton RJ, Greenaway AH. Multiplane imaging and three dimensional nanoscale particle tracking in biological microscopy. Opt Express 2010; 18:877-84. [PMID: 20173908 DOI: 10.1364/oe.18.000877] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A conventional microscope produces a sharp image from just a single object-plane. This is often a limitation, notably in cell biology. We present a microscope attachment which records sharp images from several object-planes simultaneously. The key concept is to introduce a distorted diffraction grating into the optical system, establishing an order-dependent focussing power in order to generate several images, each arising from a different object-plane. We exploit this multiplane imaging not just for bio-imaging but also for nano-particle tracking, achieving approximately 10 nm z position resolution by parameterising the images with an image sharpness metric.
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Affiliation(s)
- Paul A Dalgarno
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK.
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31
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Brunner D, Gerardot BD, Dalgarno PA, Wüst G, Karrai K, Stoltz NG, Petroff PM, Warburton RJ. A Coherent Single-Hole Spin in a Semiconductor. Science 2009; 325:70-2. [DOI: 10.1126/science.1173684] [Citation(s) in RCA: 291] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Daniel Brunner
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Brian D. Gerardot
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Paul A. Dalgarno
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Gunter Wüst
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Khaled Karrai
- Department für Physik der Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 Munich, Germany
| | - Nick G. Stoltz
- Materials Department, University of California, Santa Barbara, CA 93106, USA
| | - Pierre M. Petroff
- Materials Department, University of California, Santa Barbara, CA 93106, USA
| | - Richard J. Warburton
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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32
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Dalgarno PA, Ediger M, Gerardot BD, Smith JM, Seidl S, Kroner M, Karrai K, Petroff PM, Govorov AO, Warburton RJ. Optically induced hybridization of a quantum dot state with a filled continuum. Phys Rev Lett 2008; 100:176801. [PMID: 18518317 DOI: 10.1103/physrevlett.100.176801] [Citation(s) in RCA: 3] [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: 05/31/2007] [Revised: 01/14/2008] [Indexed: 05/26/2023]
Abstract
We present an optical signature of a hybridization between a localized quantum dot state and a filled continuum. Radiative recombination of the negatively charged trion in a single quantum dot leaves behind a single electron. We show that in two regions of vertical electric field, the electron hybridizes with a continuum through a tunneling interaction. The hybridization manifests itself through an unusual voltage dependence of the emission energy and a non-Lorentzian line shape, features which we reproduce with a theory based on the Anderson Hamiltonian.
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Affiliation(s)
- P A Dalgarno
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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33
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Kroner M, Weiss KM, Biedermann B, Seidl S, Manus S, Holleitner AW, Badolato A, Petroff PM, Gerardot BD, Warburton RJ, Karrai K. Optical detection of single-electron spin resonance in a quantum dot. Phys Rev Lett 2008; 100:156803. [PMID: 18518140 DOI: 10.1103/physrevlett.100.156803] [Citation(s) in RCA: 3] [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: 10/25/2007] [Indexed: 05/26/2023]
Abstract
We demonstrate optically detected spin resonance of a single electron confined to a self-assembled quantum dot. The dot is rendered dark by resonant optical pumping of the spin with a laser. Contrast is restored by applying a radio frequency (rf) magnetic field at the spin resonance. The scheme is sensitive even to rf fields of just a few microT. In one case, the spin resonance behaves as a driven 3-level lambda system with weak damping; in another one, the dot exhibits remarkably strong (67% signal recovery) and narrow (0.34 MHz) spin resonances with fluctuating resonant positions, evidence of unusual dynamic processes.
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Affiliation(s)
- Martin Kroner
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, München, Germany
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34
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Avron JE, Bisker G, Gershoni D, Lindner NH, Meirom EA, Warburton RJ. Entanglement on demand through time reordering. Phys Rev Lett 2008; 100:120501. [PMID: 18517847 DOI: 10.1103/physrevlett.100.120501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Indexed: 05/26/2023]
Abstract
Entangled photons can be generated "on demand" in a novel scheme involving unitary time reordering of the photons emitted in a radiative decay cascade. The scheme yields polarization entangled photon pairs, even though prior to reordering the emitted photons carry significant "which path information" and their polarizations are unentangled. This shows that quantum chronology can be manipulated in a way that is lossless and deterministic (unitary). The theory can, in principle, be tested and applied to the biexciton cascade in semiconductor quantum dots.
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Affiliation(s)
- J E Avron
- Department of Physics, Technion-Israel Institute of Technology, 32000 Haifa, Israel
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35
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Högele A, Seidl S, Kroner M, Karrai K, Schulhauser C, Sqalli O, Scrimgeour J, Warburton RJ. Fiber-based confocal microscope for cryogenic spectroscopy. Rev Sci Instrum 2008; 79:023709. [PMID: 18315307 DOI: 10.1063/1.2885681] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We describe the design and performance of a fiber-based confocal microscope for cryogenic operation. The microscope combines positioning at low temperatures along three space coordinates of millimeter translation and nanometer precision with high stability and optical performance at the diffraction limit. It was successfully tested under ambient conditions as well as at liquid nitrogen (77 K) and liquid helium (4 K) temperatures. The compact nonmagnetic design provides for long term position stability against helium refilling transfers, temperature sweeps, as well as magnetic field variation between -9 and 9 T. As a demonstration of the microscope performance, applications in the spectroscopy of single semiconductor quantum dots are presented.
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Affiliation(s)
- Alexander Högele
- Center for NanoScience, Department für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany.
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Kudelski A, Lemaître A, Miard A, Voisin P, Graham TCM, Warburton RJ, Krebs O. Optically probing the fine structure of a single Mn atom in an InAs quantum dot. Phys Rev Lett 2007; 99:247209. [PMID: 18233484 DOI: 10.1103/physrevlett.99.247209] [Citation(s) in RCA: 7] [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: 07/16/2007] [Indexed: 05/25/2023]
Abstract
We report on the optical spectroscopy of a single InAs/GaAs quantum dot doped with a single Mn atom in a longitudinal magnetic field of a few Tesla. Our findings show that the Mn impurity is a neutral acceptor state A0 whose effective spin J=1 is significantly perturbed by the quantum dot potential and its associated strain field. The spin interaction with photocarriers injected in the quantum dot is shown to be ferromagnetic for holes, with an effective coupling constant of a few hundreds of mueV, but vanishingly small for electrons.
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Affiliation(s)
- A Kudelski
- Laboratoire de Photonique et Nanostructures-CNRS, Route de Nozay, 91460 Marcoussis, France
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37
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Ediger M, Bester G, Gerardot BD, Badolato A, Petroff PM, Karrai K, Zunger A, Warburton RJ. Fine structure of negatively and positively charged excitons in semiconductor quantum dots: electron-hole asymmetry. Phys Rev Lett 2007; 98:036808. [PMID: 17358715 DOI: 10.1103/physrevlett.98.036808] [Citation(s) in RCA: 3] [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: 06/26/2006] [Indexed: 05/14/2023]
Abstract
We present new understanding of excitonic fine structure in close-to-symmetric InAs/GaAs and InGaAs/GaAs quantum dots. We demonstrate excellent agreement between spectroscopy and many-body pseudopotential theory in the energy splittings, selection rules and polarizations of the optical emissions from doubly charged excitons. We discover a marked difference between the fine structure of the doubly negatively and doubly positively charged excitons. The features in the doubly charged emission spectra are shown to arise mainly from the lack of inversion symmetry in the underlying crystal lattice.
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Affiliation(s)
- M Ediger
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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38
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Smith JM, Dalgarno PA, Warburton RJ, Govorov AO, Karrai K, Gerardot BD, Petroff PM. Voltage control of the spin dynamics of an exciton in a semiconductor quantum dot. Phys Rev Lett 2005; 94:197402. [PMID: 16090209 DOI: 10.1103/physrevlett.94.197402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Indexed: 05/03/2023]
Abstract
We report the observation of a spin-flip process in a quantum dot whereby a dark exciton with total angular momentum L = 2 becomes a bright exciton with L = 1. The spin-flip process is revealed in the decay dynamics following nongeminate excitation. We are able to control the spin-flip rate by more than an order of magnitude simply with a dc voltage. The spin-flip mechanism involves a spin exchange with the Fermi sea in the back contact of our device and corresponds to the high temperature Kondo regime. We use the Anderson Hamiltonian to calculate a spin-flip rate, and we find excellent agreement with the experimental results.
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Affiliation(s)
- J M Smith
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
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39
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Ramsay E, Pleynet N, Xiao D, Warburton RJ, Reid DT. Two-photon optical-beam-induced current solid-immersion imaging of a silicon flip chip with a resolution of 325 nm. Opt Lett 2005; 30:26-28. [PMID: 15648626 DOI: 10.1364/ol.30.000026] [Citation(s) in RCA: 4] [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] [Indexed: 05/24/2023]
Abstract
We report high-resolution subsurface imaging of a silicon flip chip by detection of the photocurrent generated by the two-photon absorption of 1530-nm light from a femtosecond Er:fiber laser. The technique combines the focal sensitivity of two-photon excitation with the enhanced optical resolution of high-numerical-aperture solid-immersion imaging. Features on a sub-1-microm scale are clearly resolvable with high contrast, showing a resolution of 325 nm.
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Affiliation(s)
- E Ramsay
- Ultrafast Optics Group, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
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40
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Högele A, Seidl S, Kroner M, Karrai K, Warburton RJ, Gerardot BD, Petroff PM. Voltage-controlled optics of a quantum dot. Phys Rev Lett 2004; 93:217401. [PMID: 15601062 DOI: 10.1103/physrevlett.93.217401] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Indexed: 05/24/2023]
Abstract
We show how the optical properties of a single semiconductor quantum dot can be controlled with a small dc voltage applied to a gate electrode. We find that the transmission spectrum of the neutral exciton exhibits two narrow lines with approximately 2 mueV linewidth. The splitting into two linearly polarized components arises through an exchange interaction within the exciton. The exchange interaction can be turned off by choosing a gate voltage where the dot is occupied with an additional electron. Saturation spectroscopy demonstrates that the neutral exciton behaves as a two-level system. Our experiments show that the remaining problem for manipulating excitonic quantum states in this system is spectral fluctuation on a mueV energy scale.
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Affiliation(s)
- Alexander Högele
- Center for NanoScience, Department für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 Munich, Germany
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41
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Karrai K, Warburton RJ, Schulhauser C, Högele A, Urbaszek B, McGhee EJ, Govorov AO, Garcia JM, Gerardot BD, Petroff PM. Hybridization of electronic states in quantum dots through photon emission. Nature 2004; 427:135-8. [PMID: 14712271 DOI: 10.1038/nature02109] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Accepted: 10/02/2003] [Indexed: 11/08/2022]
Abstract
The self-assembly of semiconductor quantum dots has opened up new opportunities in photonics. Quantum dots are usually described as 'artificial atoms', because electron and hole confinement gives rise to discrete energy levels. This picture can be justified from the shell structure observed as a quantum dot is filled either with excitons (bound electron-hole pairs) or with electrons. The discrete energy levels have been most spectacularly exploited in single photon sources that use a single quantum dot as emitter. At low temperatures, the artificial atom picture is strengthened by the long coherence times of excitons in quantum dots, motivating the application of quantum dots in quantum optics and quantum information processing. In this context, excitons in quantum dots have already been manipulated coherently. We show here that quantum dots can also possess electronic states that go far beyond the artificial atom model. These states are a coherent hybridization of localized quantum dot states and extended continuum states: they have no analogue in atomic physics. The states are generated by the emission of a photon from a quantum dot. We show how a new version of the Anderson model that describes interactions between localized and extended states can account for the observed hybridization.
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Affiliation(s)
- Khaled Karrai
- Center for NanoScience and Sektion Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany
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42
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Urbaszek B, Warburton RJ, Karrai K, Gerardot BD, Petroff PM, Garcia JM. Fine structure of highly charged excitons in semiconductor quantum dots. Phys Rev Lett 2003; 90:247403. [PMID: 12857227 DOI: 10.1103/physrevlett.90.247403] [Citation(s) in RCA: 8] [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: 10/29/2002] [Indexed: 05/24/2023]
Abstract
An exciton in a symmetric semiconductor quantum dot has two possible states, one dark and one bright, split in energy by the electron-hole exchange interaction. We demonstrate that for a doubly charged exciton, there are also two states split by the electron-hole exchange, but both states are now bright. We also uncover a fine structure in the emission from the triply charged exciton. By measuring these splittings, and also those from the singly charged and doubly charged biexcitons, all on the same quantum dot, we show how the various electron-hole exchange energies can be measured without having to break the symmetry of the dot.
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Affiliation(s)
- B Urbaszek
- Department of Physics, Heriot Watt University, Edinburgh EH14 4AS, United Kingdom
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43
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Michels JG, Daly MS, Gee P, Hill S, Nicholas RJ, Singleton J, Summers GM, Warburton RJ, Foxon CT, Harris JJ. Cyclotron resonance and spin states in GaAs/Ga1-xAlxAs heterojunctions: Experiment and theory. Phys Rev B Condens Matter 1996; 54:13807-13815. [PMID: 9985297 DOI: 10.1103/physrevb.54.13807] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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44
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Warburton RJ, Gauer C, Wixforth A, Kotthaus JP, Brar B, Kroemer H. Intersubband resonances in InAs/AlSb quantum wells: Selection rules, matrix elements, and the depolarization field. Phys Rev B Condens Matter 1996; 53:7903-7910. [PMID: 9982243 DOI: 10.1103/physrevb.53.7903] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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45
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Matsui M, Warburton RJ, Cogswell PC, Baldwin AS, Frelinger JA. Effects of HIV-1 Tat on expression of HLA class I molecules. J Acquir Immune Defic Syndr Hum Retrovirol 1996; 11:233-40. [PMID: 8603259 DOI: 10.1097/00042560-199603010-00003] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Tat protein of HIV-1 is a potent transactivator of transcription and essential for HIV-1 replication. In addition, Tat has been proposed to possess immunosuppressive functions, suggesting that Tat may play a direct role in the immune dysfunction associated with AIDS. Recently, it has been reported that Tat represses activity of a major histocompatibility complex (MHC) class I gene promoter. Because HIV infection downmodulates expression of class I molecules, this data strongly suggests that Tat downregulates class I expression and leads to loss of CTL activity. Here, we report effects of Tat on class I expression using a human cell line, T0, expressing Tat (TO-Tat). Northern blot analysis shows that levels of MHC class I transcripts are normal in T0-Tat. Flow cytometry analyses indicate that expression of HLA class I molecules is not substantially downregulated to any great extent by Tat in T0-Tat. Further, pulse-chase experiments followed by Endoglycosidase-H treatment show that the rate of maturation and processing of class I molecules in T0-Tat is indistinguishable from that in the original cell line, T0. Taken together, these data suggest that Tat expression does not necessarily result in downregulation of class I expression.
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Affiliation(s)
- M Matsui
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, 27599-7290, USA
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46
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Traynor NJ, Harley RT, Warburton RJ. Zeeman splitting and g factor of heavy-hole excitons in InxGa1-xAs/GaAs quantum wells. Phys Rev B Condens Matter 1995; 51:7361-7364. [PMID: 9977313 DOI: 10.1103/physrevb.51.7361] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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47
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Matsui M, Moots RJ, Warburton RJ, Peace-Brewer AL, Tussey LG, Quinn DG, McMichael AJ, Frelinger JA. Genetic evidence for difference between intracellular and extracellular peptides in influenza A matrix peptide-specific CTL recognition. The Journal of Immunology 1995. [DOI: 10.4049/jimmunol.154.3.1088] [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] [Indexed: 12/31/2022]
Abstract
Abstract
During the course of extensive mutagenesis of HLA-A2.1, we examined influenza A matrix peptide (FMP)-specific CTL recognition of HMy2.C1R (C1R) cells expressing mutant HLA-A2.1 molecules, sensitized with synthetic peptide, FMP 58-66, (exogenous peptide), or infected with influenza A virus (endogenous peptide). Most mutants showed equivalent presentation of exogenous and endogenous peptides to FMP-specific CTL. However, five of the mutants differed in this property. Two of the five mutants, F9L and T134K, present exogenous peptide to FMP-specific CTL, but fail to present endogenous peptide to CTL. Western blot analysis using anti-matrix protein Ab indicates that the matrix protein is expressed in these mutants after infection with virus. Interestingly, transfection of these two mutants with a minigene encoding FMP 58-66 results in efficient lysis by FMP-specific CTL. Peptide-binding assays demonstrate that the two mutations dramatically decrease the binding of FMP. However, these mutants bind FMP as well as wild type in the presence of exogenously added human beta 2-m, suggesting that the lower affinity for beta 2-m leads to the inability to present endogenous peptide. The remaining three mutants, Y27N, Q32K, and S132C, fail to present exogenous peptide, but present endogenous peptide to FMP-specific CTL. Pulse-chase analyses followed by endoglycosidase-H treatment show that the rate of maturation and processing of the five mutant HLA-A2 molecules in C1R cells is identical to that of wild type. Overall, this study suggests that the assembly and subsequent recognition of endogenous peptide differs from that of exogenous peptide.
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Affiliation(s)
- M Matsui
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - R J Moots
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - R J Warburton
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - A L Peace-Brewer
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - L G Tussey
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - D G Quinn
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - A J McMichael
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
| | - J A Frelinger
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
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48
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Matsui M, Moots RJ, Warburton RJ, Peace-Brewer AL, Tussey LG, Quinn DG, McMichael AJ, Frelinger JA. Genetic evidence for difference between intracellular and extracellular peptides in influenza A matrix peptide-specific CTL recognition. J Immunol 1995; 154:1088-96. [PMID: 7822785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
During the course of extensive mutagenesis of HLA-A2.1, we examined influenza A matrix peptide (FMP)-specific CTL recognition of HMy2.C1R (C1R) cells expressing mutant HLA-A2.1 molecules, sensitized with synthetic peptide, FMP 58-66, (exogenous peptide), or infected with influenza A virus (endogenous peptide). Most mutants showed equivalent presentation of exogenous and endogenous peptides to FMP-specific CTL. However, five of the mutants differed in this property. Two of the five mutants, F9L and T134K, present exogenous peptide to FMP-specific CTL, but fail to present endogenous peptide to CTL. Western blot analysis using anti-matrix protein Ab indicates that the matrix protein is expressed in these mutants after infection with virus. Interestingly, transfection of these two mutants with a minigene encoding FMP 58-66 results in efficient lysis by FMP-specific CTL. Peptide-binding assays demonstrate that the two mutations dramatically decrease the binding of FMP. However, these mutants bind FMP as well as wild type in the presence of exogenously added human beta 2-m, suggesting that the lower affinity for beta 2-m leads to the inability to present endogenous peptide. The remaining three mutants, Y27N, Q32K, and S132C, fail to present exogenous peptide, but present endogenous peptide to FMP-specific CTL. Pulse-chase analyses followed by endoglycosidase-H treatment show that the rate of maturation and processing of the five mutant HLA-A2 molecules in C1R cells is identical to that of wild type. Overall, this study suggests that the assembly and subsequent recognition of endogenous peptide differs from that of exogenous peptide.
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Affiliation(s)
- M Matsui
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599
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49
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Abstract
Previously, we have proposed that bovine adrenocortical mitochondrial adrenodoxin reductase may possess a domain structure, based upon the generation of two major peptide fragments from limited tryptic proteolysis. In the present study, kinetic characterization of the NADPH-dependent ferricyanide reductase activity of the partially proteolyzed enzyme demonstrates that Km(NADPH) increases (from 1.2 microM to 2.7 microM), whereas Vmax remains unaltered at 2100 min-1. The two proteolytic fragments have been purified to homogeneity by reverse-phase HPLC, and amino-acid sequence analysis unambiguously demonstrates that the 30.6 kDa fragment corresponds to the amino terminal portion of the intact protein, whereas the 22.8 kDa fragment is derived from the carboxyl terminus of the reductase. Trypsin cleavage occurs at either Arg-264 or Arg-265. Covalent crosslinking experiments using a water-soluble carbodiimide show that adrenodoxin crosslinks exclusively to the 30.6 kDa fragment, thus implicating the N-terminal region of adrenodoxin reductase in binding to the iron-sulfur protein. Our inability to detect covalent carbohydrate on either intact or proteolyzed adrenodoxin reductase prompted a re-examination of the previously reported requirement of an oligosaccharide moiety for efficient electron transfer from the reductase to adrenodoxin. Treatment of adrenodoxin reductase with a highly purified preparation of neuraminidase demonstrates that neither the adrenodoxin-independent ferricyanide reductase activity nor the adrenodoxin-dependent cytochrome c reductase activity of the enzyme is affected by neuraminidase treatment.
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Affiliation(s)
- R J Warburton
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282
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50
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Martin RW, Wong SL, Warburton RJ, Nicholas RJ, Smith AD, Gibbon MA, Thrush EJ. Variations of the hole effective masses induced by tensile strain in In1-xGaxAs(P)/InGaAsP heterostructures. Phys Rev B Condens Matter 1994; 50:7660-7667. [PMID: 9974750 DOI: 10.1103/physrevb.50.7660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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