Superconducting noise-source for ultra-low temperatures

T. M. Kim^a, S. V. Shitov<sup>ab

a</sup> National University of Science and Technology «MISIS», Moscow
^b Kotel'nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow

Abstract: The device operates at temperatures $<$ 300 mK and comprises a hafnium microbridge and a superconducting aluminum tunnel junction both integrated into a common coplanar waveguide. The microbridge is a thermodynamic source and operates as an optical blackbody at frequencies 600–700 GHz. The coplanar terminal is the blackbody output in the 1–2 GHz frequency range. The microbridge temperature can be set in the range of 0.4–9 K and calibrated using the shot noise of the tunnel junction. Activation and temperature modulation of each of the sources can be performed independently using a direct current which transit them from the superconducting to the normal state with characteristic times $<$ 0.1 ms and heating power $<$ 1 $\mu$W.

Keywords: superconducting microbridge, superconducting tunnel junction, thermodynamic noise, shot noise, noise thermometry.

Received: 01.06.2021
Revised: 21.07.2021
Accepted: 12.09.2021

DOI: 10.21883/PJTF.2021.24.51791.18897

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