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BETA
Jöns, Klaus D.
Publications (10 of 15) Show all publications
Fognini, A., Ahmadi, A., Zeeshan, M., Fokkens, J. T., Gibson, S. J., Sherlekar, N., . . . Reimer, M. E. (2019). Dephasing Free Photon Entanglement with a Quantum Dot. ACS Photonics, 6(7), 1656-1663
Open this publication in new window or tab >>Dephasing Free Photon Entanglement with a Quantum Dot
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2019 (English)In: ACS Photonics, E-ISSN 2330-4022, Vol. 6, no 7, p. 1656-1663Article in journal (Refereed) Published
Abstract [en]

Generation of photon pairs from quantum dots with near-unity entanglement fidelity has been a long-standing scientific challenge. It is generally thought that the nuclear spins limit the entanglement fidelity through spin flip dephasing processes. However, this assumption lacks experimental support. Here, we show two-photon entanglement with negligible dephasing from an indium rich single quantum dot comprising a nuclear spin of 9/2 when excited quasi-resonantly. This finding is based on a significantly close match between our entanglement measurements and our model that assumes no dephasing and takes into account the detection system's timing jitter and dark counts. We suggest that neglecting the detection system is responsible for the degradation of the measured entanglement fidelity in the past and not the nuclear spins. Therefore, the key to unity entanglement from quantum dots comprises a resonant excitation scheme and a detection system with ultralow timing jitter and dark counts.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
entanglement, fine-structure splitting, quantum dot, single photons
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-255771 (URN)10.1021/acsphotonics.8b01496 (DOI)000476684300012 ()2-s2.0-85067950170 (Scopus ID)
Note

QC 20190812

Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Basset, F. B., Rota, M. B., Schimpf, C., Tedeschi, D., Zeuner, K., da Silva, S. F., . . . Trotta, R. (2019). Entanglement Swapping with Photons Generated on Demand by a Quantum Dot. Physical Review Letters, 123(16), Article ID 160501.
Open this publication in new window or tab >>Entanglement Swapping with Photons Generated on Demand by a Quantum Dot
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2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 123, no 16, article id 160501Article in journal (Refereed) Published
Abstract [en]

Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of nonclassical light were used for seminal demonstration of entanglement swapping, but applications in quantum technologies demand push-button operation requiring single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent prerequisites on the efficiency and purity of the generation of entangled states. Here we show a proof-of-concept demonstration of all-photonic entanglement swapping with pairs of polarization-entangled photons generated on demand by a GaAs quantum dot without spectral and temporal filtering. Moreover, we develop a theoretical model that quantitatively reproduces the experimental data and provides insights on the critical figures of merit for the performance of the swapping operation. Our theoretical analysis also indicates how to improve stateof-the-art entangled-photon sources to meet the requirements needed for implementation of quantum dots in long-distance quantum communication protocols.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2019
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-262938 (URN)10.1103/PhysRevLett.123.160501 (DOI)000489831500001 ()2-s2.0-85073813116 (Scopus ID)
Note

QC 20191129

Available from: 2019-11-29 Created: 2019-11-29 Last updated: 2019-11-29Bibliographically approved
Schöll, E., Hanschke, L., Schweickert, L., Zeuner, K. D., Reindl, M., da Silva, S. F., . . . Jöns, K. D. (2019). Resonance Fluorescence of GaAs Quantum Dots with Near-Unity Photon Indistinguishability. Nano letters (Print), 19(4), 2404-2410
Open this publication in new window or tab >>Resonance Fluorescence of GaAs Quantum Dots with Near-Unity Photon Indistinguishability
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2019 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, no 4, p. 2404-2410Article in journal (Refereed) Published
Abstract [en]

Photonic quantum technologies call for scalable quantum light sources that can be integrated, while providing the end user with single and entangled photons on demand. One promising candidate is strain free GaAs/A1GaAs quantum dots obtained by aluminum droplet etching. Such quantum dots exhibit ultra low multi-photon probability and an unprecedented degree of photon pair entanglement. However, different to commonly studied InGaAs/GaAs quantum dots obtained by the Stranski-Krastanow mode, photons with a near-unity indistinguishability from these quantum emitters have proven to be elusive so far. Here, we show on-demand generation of near-unity indistinguishable photons from these quantum emitters by exploring pulsed resonance fluorescence. Given the short intrinsic lifetime of excitons and trions confined in the GaAs quantum dots, we show single photon indistinguishability with a raw visibility of V-raw = (95.0(-6.1)(+5.0))%, without the need for Purcell enhancement. Our results represent a milestone in the advance of GaAs quantum dots by demonstrating the final missing property standing in the way of using these emitters as a key component in quantum communication applications, e.g., as quantum light sources for quantum repeater architectures.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
Keywords
Semiconductor quantum dot, resonance fluorescence, indistinguishable photons, Al droplet etching
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-251341 (URN)10.1021/acs.nanolett.8b05132 (DOI)000464769100028 ()30862165 (PubMedID)2-s2.0-85063372001 (Scopus ID)
Note

QC 20190521

Available from: 2019-05-21 Created: 2019-05-21 Last updated: 2019-05-21Bibliographically approved
Reindl, M., Huber, D., Schimpf, C., da Silva, S. F. C., Rota, M. B., Huang, H., . . . Trotta, R. (2018). All-photonic quantum teleportation using on-demand solid-state quantum emitters. Science Advances, 4(12), Article ID eaau1255.
Open this publication in new window or tab >>All-photonic quantum teleportation using on-demand solid-state quantum emitters
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2018 (English)In: Science Advances, E-ISSN 2375-2548, Vol. 4, no 12, article id eaau1255Article in journal (Refereed) Published
Abstract [en]

All-optical quantum teleportation lies at the heart of quantum communication science and technology. This quantum phenomenon is built up around the nonlocal properties of entangled states of light that, in the perspective of real-life applications, should be encoded on photon pairs generated on demand. Despite recent advances, however, the exploitation of deterministic quantum light sources in push-button quantum teleportation schemes remains a major open challenge. Here, we perform an important step toward this goal and show that photon pairs generated on demand by a GaAs quantum dot can be used to implement a teleportation protocol whose fidelity violates the classical limit (by more than 5 SDs) for arbitrary input states. Moreover, we develop a theoretical framework that matches the experimental observations and that defines the degree of entanglement and indistinguishability needed to overcome the classical limit independently of the input state. Our results emphasize that on-demand solid-state quantum emitters are one of the most promising candidates to realize deterministic quantum teleportation in practical quantum networks.

Place, publisher, year, edition, pages
AMER ASSOC ADVANCEMENT SCIENCE, 2018
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-241227 (URN)10.1126/sciadv.aau1255 (DOI)000454369600018 ()30555916 (PubMedID)2-s2.0-85058757029 (Scopus ID)
Note

QC 20190117

Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-01-17Bibliographically approved
Haffouz, S., Zeuner, K. D., Dalacu, D., Poole, P. J., Lapointe, J., Poitras, D., . . . Williams, R. L. (2018). Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires: The Role of the Photonic Waveguide. Nano letters (Print), 18(5), 3047-3052
Open this publication in new window or tab >>Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires: The Role of the Photonic Waveguide
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2018 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, no 5, p. 3047-3052Article in journal (Refereed) Published
Abstract [en]

We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in the count rate by nearly 2 orders of magnitude (0.4 to 35 kcps) is obtained for quantum dots emitting in the telecom O-band, showing high single-photon purity with multiphoton emission probabilities down to 2%. Using emission-wavelength-optimized waveguides, we demonstrate bright, narrow-line-width emission from single InAsP quantum dots with an unprecedented tuning range of 880 to 1550 nm. These results pave the way toward efficient single-photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
Quantum dot, nanowire, selective growth, vapor-liquid-solid, epitaxial growth, chemical beam epitaxy, photoluminescence, single-photon source
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-229029 (URN)10.1021/acs.nanolett.8b00550 (DOI)000432093200043 ()29616557 (PubMedID)
Funder
EU, European Research Council, 307687Swedish Research Council, 638-2013-7152
Note

QC 20180531

Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2018-05-31Bibliographically approved
Schweickert, L., Jöns, K. D., Lettner, T., Zeuner, K., Zichi, J., Elshaari, A. W., . . . Zwiller, V. (2018). Generating, manipulating and detecting quantum states of light at the nanoscale. In: Optics InfoBase Conference Papers: . Paper presented at Latin America Optics and Photonics Conference, LAOP 2018, 12 November 2018 through 15 November 2018. OSA - The Optical Society
Open this publication in new window or tab >>Generating, manipulating and detecting quantum states of light at the nanoscale
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2018 (English)In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper, Published paper (Refereed)
Abstract [en]

We generate, manipulate and detect light at the single photon level with semiconducting and superconducting nanowires.

Place, publisher, year, edition, pages
OSA - The Optical Society, 2018
Keywords
Light, Particle beams, Photonics, Nano scale, Quantum state, Single-photon level, Superconducting nanowire, Quantum theory
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-247434 (URN)10.1364/LAOP.2018.Tu5D.3 (DOI)2-s2.0-85059482342 (Scopus ID)9781943580491 (ISBN)
Conference
Latin America Optics and Photonics Conference, LAOP 2018, 12 November 2018 through 15 November 2018
Note

QC20190418

Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-04-18Bibliographically approved
Elshaari, A. W., Esmaeil Zadeh, I., Fognini, A., Dalacu, D., Poole, P. J., Reimer, M. E., . . . Jöns, K. D. (2018). Hybrid quantum photonic integrated circuits. In: Proceedings - International Conference Laser Optics 2018, ICLO 2018: . Paper presented at 2018 International Conference Laser Optics, ICLO 2018, St. Petersburg, Russian Federation, 4 June 2018 through 8 June 2018. Institute of Electrical and Electronics Engineers (IEEE), Article ID 8435508.
Open this publication in new window or tab >>Hybrid quantum photonic integrated circuits
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2018 (English)In: Proceedings - International Conference Laser Optics 2018, ICLO 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, article id 8435508Conference paper, Published paper (Refereed)
Abstract [en]

Quantum photonic integrated circuits require a scalable approach to integrate bright on-demand sources of entangled photon-pairs in complex on-chip quantum photonic circuits. Currently, the most promising sources are based on III/V semiconductor quantum dots. However, complex photonic circuitry is mainly achieved in silicon photonics due to the tremendous technological challenges in circuit fabrication. We take the best of both worlds by developing a new hybrid on-chip nanofabrication approach, allowing to integrate III/V semiconductor nanowire quantum emitters into silicon-based photonics.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Quantum dots, Quantum photonic circuits, Semiconductor nanowires, SIN waveguides, Singlephoton source
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-234485 (URN)10.1109/LO.2018.8435508 (DOI)2-s2.0-85052512010 (Scopus ID)9781538636121 (ISBN)
Conference
2018 International Conference Laser Optics, ICLO 2018, St. Petersburg, Russian Federation, 4 June 2018 through 8 June 2018
Note

QC 20180907

Available from: 2018-09-07 Created: 2018-09-07 Last updated: 2018-09-07Bibliographically approved
Leandro, L., Gunnarsson, C. P., Reznik, R., Jöns, K. D., Shtrom, I., Khrebtov, A., . . . Akopian, N. (2018). Nanowire Quantum Dots Tuned to Atomic Resonances. Nano letters (Print), 18(11), 7217-7221
Open this publication in new window or tab >>Nanowire Quantum Dots Tuned to Atomic Resonances
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2018 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, no 11, p. 7217-7221Article in journal (Refereed) Published
Abstract [en]

Quantum dots tuned to atomic resonances represent an emerging field of hybrid quantum systems where the advantages of quantum dots and natural atoms can be combined. Embedding quantum dots in nanowires boosts these systems with a set of powerful possibilities, such as precise positioning of the emitters, excellent photon extraction efficiency and direct electrical contacting of quantum dots. Notably, nanowire structures can be grown on silicon substrates, allowing for a straightforward integration with silicon-based photonic devices. In this work we show controlled growth of nanowire-quantum-dot structures on silicon, frequency tuned to atomic transitions. We grow GaAs quantum dots in AlGaAs nanowires with a nearly pure crystal structure and excellent optical properties. We precisely control the dimensions of quantum dots and their position inside nanowires and demonstrate that the emission wavelength can be engineered over the range of at least 30 nm around 765 nm. By applying an external magnetic field, we are able to fine-tune the emission frequency of our nanowire quantum dots to the D-2 transition of Rb-87. We use the Rb transitions to precisely measure the actual spectral line width of the photons emitted from a nanowire quantum dot to be 9.4 +/- 0.7 mu eV, under nonresonant excitation. Our work brings highly desirable functionalities to quantum technologies, enabling, for instance, a realization of a quantum network, based on an arbitrary number of nanowire single-photon sources, all operating at the same frequency of an atomic transition.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
Nanowires, quantum dots, hybrid systems, VLS growth, GaAs/AlGaAs
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-240011 (URN)10.1021/acs.nanolett.8b03363 (DOI)000451102100076 ()30336054 (PubMedID)2-s2.0-85055343147 (Scopus ID)
Note

QC 20181210

Available from: 2018-12-10 Created: 2018-12-10 Last updated: 2018-12-10Bibliographically approved
Elshaari, A. W., Buyukozer, E., Zadeh, I. E., Lettner, T., Zhao, P., Schöll, E., . . . Zwiller, V. (2018). Strain-Tunable Quantum Integrated Photonics. Nano letters (Print), 18(12), 7969-7976
Open this publication in new window or tab >>Strain-Tunable Quantum Integrated Photonics
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2018 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, no 12, p. 7969-7976Article in journal (Refereed) Published
Abstract [en]

Semiconductor quantum dots are crucial parts of the photonic quantum technology toolbox because they show excellent single-photon emission properties in addition to their potential as solid-state qubits. Recently, there has been an increasing effort to deterministically integrate single semiconductor quantum dots into complex photonic circuits. Despite rapid progress in the field, it remains challenging to manipulate the optical properties of waveguide-integrated quantum emitters in a deterministic, reversible, and nonintrusive manner. Here we demonstrate a new class of hybrid quantum photonic circuits combining III V semiconductors, silicon nitride, and piezoelectric crystals. Using a combination of bottom-up, top-down, and nanomanipulation techniques, we realize strain tuning of a selected, waveguide-integrated, quantum emitter and a planar integrated optical resonator. Our findings are an important step toward realizing reconfigurable quantum-integrated photonics, with full control over the quantum sources and the photonic circuit.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
Nanowires, strain tuning, quantum dot, quantum integrated photonics, ring resonator, single photon
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-240745 (URN)10.1021/acs.nanolett.8b03937 (DOI)000453488800074 ()30474987 (PubMedID)2-s2.0-85058112477 (Scopus ID)
Funder
Swedish Research Council, 2016-03905
Note

QC 20190108

Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-01-08Bibliographically approved
Jöns, K. D., Schweickert, L., Versteegh, M. A. M., Dalacu, D., Poole, P. J., Gulinatti, A., . . . Reimer, M. E. (2017). Erratum to: Bright nanoscale source of deterministic entangled photon pairs violating Bell’s inequality (Scientific Reports, (2017), 7, 1, (1700), 10.1038/s41598-017-01509-6). Scientific Reports, 7(1), Article ID 7751.
Open this publication in new window or tab >>Erratum to: Bright nanoscale source of deterministic entangled photon pairs violating Bell’s inequality (Scientific Reports, (2017), 7, 1, (1700), 10.1038/s41598-017-01509-6)
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2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, no 1, article id 7751Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Nature Publishing Group, 2017
Keywords
erratum
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-236457 (URN)10.1038/s41598-017-07625-7 (DOI)000407400100038 ()2-s2.0-85051292610 (Scopus ID)
Note

QC 20181022

Available from: 2018-10-22 Created: 2018-10-22 Last updated: 2019-10-17Bibliographically approved
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