Single-Photon Single-Flux Coupled Detectors

TL;DR

This paper introduces a novel superconducting device combining a single-photon detector with a multi-level memory, enabling photon counting through single-flux conversion and demonstrating potential for advanced quantum sensing.

Contribution

The work presents a new integrated device that combines photon detection and flux-based memory, with detailed electrical and optical characterization, and discusses improvements and arraying strategies.

Findings

Demonstrated single-flux quantum separated states.

Differentiated single-photon detection from other phenomena.

Explored device geometries and materials for performance enhancement.

Abstract

In this work, we present a novel device that is a combination of a superconducting nanowire single-photon detector and a superconducting multi-level memory. We show that these devices can be used to count the number of detections through single-photon to single-flux conversion. Electrical characterization of the memory properties demonstrates single-flux quantum (SFQ) separated states. Optical measurements using attenuated laser pulses with different mean photon number, pulse energies and repetition rates are shown to differentiate single-photon detection from other possible phenomena, such as multi-photon detection and thermal activation. Finally, different geometries and material stacks to improve device performance, as well as arraying methods are discussed.