Photon-number resolving detector based on a series array of superconducting nanowires

TL;DR

This paper demonstrates a superconducting photon number resolving detector using a series array of nanowires, capable of distinguishing photon counts with potential for scalability and improved efficiency.

Contribution

It introduces a novel series nanowire array design for photon number resolution with experimental validation and promising scalability.

Findings

Successfully distinguished 1-4 photon events

Achieved a quantum efficiency of 2.6% at 1300nm

Demonstrated potential for scalable photon number detection

Abstract

We present the experimental demonstration of a superconducting photon number resolving detector. It is based on the series connection of N superconducting nanowires, each connected in parallel to an integrated resistor. The device provides a single voltage readout, proportional to the number of photons absorbed in distinct nanowires. Clearly separated output levels corresponding to the detection of n=1-4 photons are observed in a 4-element detector fabricated from an NbN film on GaAs substrate, with a single-photon system quantum efficiency of 2.6% at the wavelength of 1300nm. The series-nanowire structure is promising in view of its scalability to large photon numbers and high efficiencies.