Proximity SQUID single photon detector via temperature-to-voltage conversion

TL;DR

This paper introduces a novel superconducting quantum interference device (SQUID) based single photon detector that converts photon-induced temperature changes into measurable voltage signals, capable of high-frequency photon discrimination.

Contribution

The paper presents a new SQUID-based photon detector utilizing temperature-to-voltage conversion, enhancing photon detection and frequency discrimination capabilities.

Findings

Detects photons above 5 THz with SNR > 20

Operates effectively between 0.1 K and 0.5 K

Robust against thermal noise perturbations

Abstract

We propose a single photon detector based on a superconducting quantum interference device (SQUID) with superconductor-normal metal-superconductor Josephson weak links. One of the two Josephson junctions is connected to an antenna, and is heated when a photon is absorbed. The increase of the weak link temperature exponentially suppresses the Josephson critical current thereby inducing an asymmetry in the SQUID. This generates a voltage pulse across the SQUID that can be measured with a threshold detector. Realized with realistic parameters the device can be used as a single photon detector, and as a calorimeter since it is able to discriminate photons frequency above $5~$THz with a signal-to-noise ratio larger than $20$. The detector performance are robust with respect to working temperatures between $0.1~$ K and $0.5~$K, and thermal noise perturbation.