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  • APCTP SEMINAR (Online & On-site): Graphene-based Josephson junction microwave bolometer
  • 작성자 관리자 등록일 2020-11-30 조회수 233
  • APCTP SEMINAR (Online & On-site)

     

    Title: Graphene-based Josephson junction microwave bolometer
    Speaker: Prof. Gil-Ho Lee (POSTECH, APCTP)
    • Host: Prof. Yunkyu Bang (APCTP, POSTECH)
    Date & Time: Dec. 16 (Wed.) / 16:00 (KST)
    • Venue: #512, APCTP HQ & Online via ZOOM
    • ZOOM Link: https://zoom.us/meeting/register/tJEkceGvrzsiEtXg1wia86TrvXdgMpBazAjN
     

     

    Overview

    Sensitive microwave detectors are critical instruments in radioastronomy, dark matter axion searches, and superconducting quantum information science. The conventional strategy towards higher-sensitivity bolometry is to nanofabricate an ever-smaller device to augment the thermal response. However, this direction is increasingly more difficult to obtain efficient photon coupling and maintain the material properties in a device with a large surface-to- volume ratio. Here we advance this concept to an ultimately thin bolometric sensor based on monolayer graphene. To utilize its minute electronic specific heat and thermal conductivity, we develop a superconductor-graphene-superconductor (SGS) Josephson junction bolometer embedded in a microwave resonator of resonance frequency 7.9 GHz with over 99% coupling efficiency. From the dependence of the Josephson switching current on the operating temperature, charge density, input power, and frequency, we demonstrate a noise equivalent power (NEP) of 7×10-19 W/Hz1/2 , corresponding to an energy resolution of one single-photon at 32 GHz and reaching the fundamental limit imposed by the intrinsic thermal fluctuation at 0.19 K.

     

     

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