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arXiv:1703.09736 · Physical Review Applied

Graphene-Based Josephson-Junction Single-Photon Detector

Evan D. Walsh, Dmitri K. Efetov, Gil‐Ho Lee, Mikkel Heuck, Jesse Crossno, Thomas Ohki, Philip Kim, Dirk Englund, Kin Chung Fong

Published Aug 24, 2017• 99 citations
arXivHTMLPDF

Abstract

Detecting single photons is essential for numerous technologies, from quantum computing to observations of the faintest objects in the universe. The authors propose a detector based on graphene's dual abilities to absorb light across a huge range of wavelengths, and to experience an extreme rise in electronic temperature by absorbing just one photon. Simulations show that these properties allow for high detection efficiency, when the graphene is coupled to superconductors in a Josephson junction at cryogenic temperatures.

DOI
10.1103/physrevapplied.8.024022

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Quantum Devices Josephson junctions are simple superconducting devices comprising an insulator or semiconductor separating two superconducting regions. They form the workhorse of superconducting technologies and are exquisitely sensitive to magnetic field. One long-sought proposal has been to use these devices to detect light. Walsh et al. have realized a photosensitive Josephson junction based on graphene that is capable of sensing single infrared photons. Such a photosensitive Josephson junction is expected to operate as a high-speed, low-power consumption optical interconnect for communication between superconducting-based supercomputers and quantum computers. Science , this issue p. [409][1] [1]: /lookup/doi/10.1126/science.abf5539

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Detecting single photons is essential for numerous technologies, from quantum computing to observations of the faintest objects in the universe. The authors propose a detector based on graphene's dual abilities to absorb light across a huge range of wavelengths, and to experience an extreme rise in electronic temperature by absorbing just one photon. Simulations show that these properties allow for high detection efficiency, when the graphene is coupled to superconductors in a Josephson junction at cryogenic temperatures.
We propose to use graphene-based Josephson junctions (GJJs) to detect single photons in a wide electromagnetic spectrum from visible to radio frequencies. Our approach takes advantage of the exceptionally low electronic heat capacity of monolayer graphene and its constricted thermal conductance to its phonon degrees of freedom. Such a system could provide high-sensitivity photon detection required for research areas including quantum information processing and radio astronomy. As an example, we present our device concepts for GJJ single-photon detectors in both the microwave and infrared regimes. The dark count rate and intrinsic quantum efficiency are computed based on parameters from a measured GJJ, demonstrating feasibility within existing technologies.
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Josephson junctions are superconducting devices used as high-sensitivity magnetometers and voltage amplifiers as well as the basis of high-performance cryogenic computers and superconducting quantum computers. Although device performance can be degraded by the generation of quasiparticles formed from broken Cooper pairs, this phenomenon also opens opportunities to sensitively detect electromagnetic radiation. We demonstrate single near-infrared photon detection by coupling photons to the localized surface plasmons of a graphene-based Josephson junction. Using the photon-induced switching statistics of the current-biased device, we reveal the critical role of quasiparticles generated by the absorbed photon in the detection mechanism. The photon sensitivity will enable a high-speed, low-power optical interconnect for future superconducting computing architectures.
A junction for single-photon detection Josephson junctions are simple superconducting devices comprising an insulator or semiconductor separating two superconducting regions. They form the workhorse of superconducting technologies and are exquisitely sensitive to magnetic field. One long-sought proposal has been to use these devices to detect light. Walsh et al. have realized a photosensitive Josephson junction based on graphene that is capable of sensing single infrared photons. Such a photosensitive Josephson junction is expected to operate as a high-speed, low-power consumption optical interconnect for communication between superconducting-based supercomputers and quantum computers. Science , this issue p. 409
Graphene Josephson junctions (JJ) provide a promising platform for ultra-broadband quantum sensing of light owing to graphene's frequency-independent absorption, vanishing electronic heat capacity, and weak electron-phonon coupling, which enable rapid suppression of the critical current through radiation-induced electron heating. Existing investigations have been confined to the microwave and infrared regimes, where competing detector technologies are already established; by contrast, the terahertz (THz) band - where sensitivity is most urgently lacking and no mature quantum sensor exists - has remained largerly unexplored. Here we demonstrate a strong photoresponse of graphene JJs at THz frequencies, establishing a first experimental step towards graphene-based THz quantum sensors. Under low-intensity illumination, we observe a pronounced suppression of the critical current that generates a strong photovoltage (Vph) under current bias. By tracking this Vph and independently measuring the electron temperature as a function of absorbed power, we extract a responsivity of 88 kV W^-1 and a noise-equivalent power of 45 aW Hz^-1/2 at 1.7 K. Furthermore, gate tunability of our JJ enables access to a regime where hysteretic current-voltage characteristics persist up to 0.9 K, offering a potential route toward single-photon THz detection beyond millikelvin (mK) temperatures. These findings establish graphene JJ as a versatile platform for broadband cryogenic radiation sensing and point towards their use as quantum sensors at THz frequencies.
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