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Journal ArticleDOI

Detecting single infrared photons with 93% system efficiency

TL;DR: In this article, a fiber-coupled single-photon detection system using amorphous tungsten silicide superconducting nanowire detectors was developed, and the system detection efficiency was higher than 90% in the wavelength range between 1520 nm and 1610 nm.
Abstract: Researchers develop a fiber-coupled single-photon-detection system using amorphous tungsten silicide superconducting nanowire single-photon detectors. The system detection efficiency is higher than 90% in the wavelength range between 1520 nm and 1610 nm. The device dark-count rate, timing jitter and reset time are 1 cps, 150 ps and 40 ns, respectively.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors present a loophole-free violation of local realism using entangled photon pairs, ensuring that all relevant events in their Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements.
Abstract: We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment.

1,201 citations

Journal ArticleDOI
TL;DR: An overview is given of the state-of-the-art research into secure communication based on quantum cryptography, together with its assumptions, strengths and weaknesses.
Abstract: An overview is given of the state-of-the-art research into secure communication based on quantum cryptography. The present security model together with its assumptions, strengths and weaknesses is discussed. Recent experimental progress and remaining challenges are surveyed as are the latest developments in quantum hacking and countermeasures.

1,052 citations

Journal ArticleDOI
TL;DR: In the past 20 years, impressive progress has been made both experimentally and theoretically in superconducting quantum circuits, which provide a platform for manipulating microwave photons as mentioned in this paper, and many higher-order effects, unusual and less familiar in traditional cavity quantum electrodynamics with natural atoms, have been experimentally observed.

909 citations

Journal ArticleDOI
TL;DR: By s-shell pulsed resonant excitation of a Purcell-enhanced quantum dot-micropillar system, deterministically generate resonance fluorescence single photons which, at π pulse excitation, have an extraction efficiency of 66, single-photon purity of 99.1%, and photon indistinguishability of 98.5%.
Abstract: This work was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the National Fundamental Research Program. We acknowledge financial support by the State of Bavaria and the German Ministry of Education and Research (BMBF) within the projects Q.com-H and the Chist-era project SSQN. N. G. acknowledges support from the Danish Research Council for Technology and Production.

839 citations

Journal ArticleDOI
TL;DR: The UWBG semiconductor materials, such as high Al‐content AlGaN, diamond and Ga2O3, advanced in maturity to the point where realizing some of their tantalizing advantages is a relatively near‐term possibility.
Abstract: J. Y. Tsao,* S. Chowdhury, M. A. Hollis,* D. Jena, N. M. Johnson, K. A. Jones, R. J. Kaplar,* S. Rajan, C. G. Van de Walle, E. Bellotti, C. L. Chua, R. Collazo, M. E. Coltrin, J. A. Cooper, K. R. Evans, S. Graham, T. A. Grotjohn, E. R. Heller, M. Higashiwaki, M. S. Islam, P. W. Juodawlkis, M. A. Khan, A. D. Koehler, J. H. Leach, U. K. Mishra, R. J. Nemanich, R. C. N. Pilawa-Podgurski, J. B. Shealy, Z. Sitar, M. J. Tadjer, A. F. Witulski, M. Wraback, and J. A. Simmons

785 citations

References
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Book
01 May 1971

2,937 citations

Journal ArticleDOI
12 Sep 2010-Nature
TL;DR: A number of physical systems, spanning much of modern physics, are being developed for this task, ranging from single particles of light to superconducting circuits, and it is not yet clear which, if any, will ultimately prove successful as discussed by the authors.
Abstract: Quantum mechanics---the theory describing the fundamental workings of nature---is famously counterintuitive: it predicts that a particle can be in two places at the same time, and that two remote particles can be inextricably and instantaneously linked These predictions have been the topic of intense metaphysical debate ever since the theory's inception early last century However, supreme predictive power combined with direct experimental observation of some of these unusual phenomena leave little doubt as to its fundamental correctness In fact, without quantum mechanics we could not explain the workings of a laser, nor indeed how a fridge magnet operates Over the last several decades quantum information science has emerged to seek answers to the question: can we gain some advantage by storing, transmitting and processing information encoded in systems that exhibit these unique quantum properties? Today it is understood that the answer is yes Many research groups around the world are working towards one of the most ambitious goals humankind has ever embarked upon: a quantum computer that promises to exponentially improve computational power for particular tasks A number of physical systems, spanning much of modern physics, are being developed for this task---ranging from single particles of light to superconducting circuits---and it is not yet clear which, if any, will ultimately prove successful Here we describe the latest developments for each of the leading approaches and explain what the major challenges are for the future

2,301 citations

Journal ArticleDOI
TL;DR: In this article, a supercurrent-assisted hotspot-formation mechanism for ultrafast detection and counting of visible and infrared photons is presented, where a photon-induced hotspot leads to a temporary formation of a resistive barrier across the superconducting sensor strip and results in an easily measurable voltage pulse.
Abstract: We experimentally demonstrate a supercurrent-assisted, hotspot-formation mechanism for ultrafast detection and counting of visible and infrared photons. A photon-induced hotspot leads to a temporary formation of a resistive barrier across the superconducting sensor strip and results in an easily measurable voltage pulse. Subsequent hotspot healing in ∼30 ps time frame, restores the superconductivity (zero-voltage state), and the detector is ready to register another photon. Our device consists of an ultrathin, very narrow NbN strip, maintained at 4.2 K and current-biased close to the critical current. It exhibits an experimentally measured quantum efficiency of ∼20% for 0.81 μm wavelength photons and negligible dark counts.

1,529 citations

Journal ArticleDOI
TL;DR: The current state of research and future directions in quantum key distribution and quantum networks are reviewed in this paper, with a special emphasis on quantum key distributions and quantum key sharing in quantum networks.
Abstract: Quantum communication, and indeed quantum information in general, has changed the way we think about quantum physics In 1984 and 1991, the first protocol for quantum cryptography and the first application of quantum non-locality, respectively, attracted a diverse field of researchers in theoretical and experimental physics, mathematics and computer science Since then we have seen a fundamental shift in how we understand information when it is encoded in quantum systems We review the current state of research and future directions in this new field of science with special emphasis on quantum key distribution and quantum networks

1,420 citations

Journal ArticleDOI
TL;DR: The current status of single-photon-source and single-Photon-detector technologies operating at wavelengths from the ultraviolet to the infrared are reviewed and applications of these technologies to quantum communication are discussed.
Abstract: We review the current status of single-photon-source and single-photon-detector technologies operating at wavelengths from the ultraviolet to the infrared. We discuss applications of these technologies to quantum communication, a field currently driving much of the development of single-photon sources and detectors.

1,280 citations