Physics of Proximity Josephson Sensor

TL;DR

This paper investigates the physics and optimization of the proximity Josephson sensor across various temperature ranges, focusing on radiation absorption, nonequilibrium states, and material considerations like graphene.

Contribution

It provides a detailed analysis of how proximity effects influence sensor response and explores the potential of graphene as an absorber material.

Findings

Sensor operates in a weak nonequilibrium state under irradiation

Proximity effects alter electron-phonon coupling and noise

Graphene's suitability as an absorber is evaluated

Abstract

We study the proximity Josephson sensor (PJS) in both bolometric and calorimetric operation and optimize it for different temperature ranges between 25 mK and a few Kelvin. We investigate how the radiation power is absorbed in the sensor and find that the irradiated sensor is typically in a weak nonequilibrium state. We show in detail how the proximity of the superconductors affects the device response: for example via changes in electron-phonon coupling and out-of-equilibrium noise. In addition, we estimate the applicability of graphene as the absorber material.