A highly-sensitive broadband superconducting thermoelectric single-photon detector

TL;DR

This paper introduces a superconducting thermoelectric single-photon detector capable of broadband operation from GHz to PHz frequencies, converting photon absorption into measurable thermovoltage with high sensitivity and potential for various quantum applications.

Contribution

It presents a novel passive superconducting thermoelectric detector based on bipolar effects in tunnel junctions, enabling broadband single-photon detection with high signal-to-noise ratio.

Findings

Detects single photons from 15 GHz to 150 PHz.

Achieves SNR of about 15 at 50 GHz at 10 mK.

Can discern photon energy by thermovoltage persistence.

Abstract

We propose a passive single-photon detector based on the bipolar thermoelectric effect occurring in tunnel junctions between two different superconductors thanks to spontaneous electron-hole symmetry breaking. Our thermoelectric detector (TED) converts a finite temperature difference caused by the absorption of a single photon into an open circuit thermovoltage. Designed with feasible parameters, our TED is able to reveal single-photons of frequency ranging from about 15 GHz to about 150 PHz depending on the chosen design and materials. In particular, this detector is expected to show values of signal-to-noise ratio SNR about 15 at {\nu} = 50 GHz when operated at a temperature of 10 mK. Interestingly, this device can be viewed as a digital single-photon detector, since it generates an almost constant voltage VS for the full operation energies. Our TED can reveal single photons in a frequency range wider than 4 decades with the possibility to discern the energy of the incident photon by measuring the time persistence of the generated thermovoltage. Its broadband operation suggests that our TED could find practical applications in several fields of quantum science and technology, such as quantum computing, telecommunications, optoelectronics, THz spectroscopy and astro-particle physics.