Potentials of Josephson junctions for millimeterwave radio astronomy.

Junji Inatani

Syozo Imai, Seizo Morita, Yosihisa Takeuti +1 more

There are growing needs for low noise and wide band receiver in SMMW range, e.g., in radio astronomy [1]. Hitherto, Schottky diode mixer, Josephson mixer using point contact microbridges, and quasiparticle mixer using superconducting tunnel junctions have been investigated intensively in MMW range. Over wide SMMW range, however, only Schottky diode mixer was tested and used at present. Quasiparticle mixer now confronts a basic difficulty for operation in SMMW range, although it has very high potential as a SMMW mixer. On the otherhand, potential of Josephson mixer using microbridges is unclear.

C. C. Grimes

Hiroshi Ohta

Gil‐Ho Lee, Jesse Crossno, Thomas Ohki +6 more

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.

Alexander N. Vystavkin, Vladimir N. Gubankov, V. P. Diakov +1 more