Cascade switching current detectors based on arrays of Josephson junctions

TL;DR

This paper introduces superconducting photon detectors using arrays of Josephson junctions that amplify signals via cascade switching, promising highly sensitive broadband THz sensors.

Contribution

It presents novel cascade-amplified superconducting detectors with arrays of Josephson junctions, demonstrating avalanche-like switching for enhanced sensitivity.

Findings

Demonstrated cascade amplification in superconducting detectors.

Achieved antenna effects indicating good impedance matching.

Potential for broadband THz sensors with sensitivity over 10^13 V/W.

Abstract

Cascade multiplication is a common technique to enhance the sensitivity of photon detectors. In this study, we demonstrate novel cascade-amplified superconducting detectors utilizing arrays of Josephson junctions. The mutual coupling between junctions induces avalanche-like switching of multiple junctions upon photon absorption, leading to cascade amplification of the readout voltage. We present two prototypes featuring either low-Tc linear Nb/NbxSi1-x/Nb arrays, or high-Tc stacked intrinsic Josephson junctions. Both devices exhibit clear antenna effects in microwave directivities, indicating good impedance matching and absorption efficiency. The combination of high absorption efficiency and large cascade amplification has the potential to produce broadband THz sensors with sensitivity exceeding 10^13 V/W.