Characterization of a photon-number resolving SNSPD using Poissonian and sub-Poissonian light

TL;DR

This paper presents a superconducting nanowire single-photon detector capable of resolving up to four photons, demonstrating high accuracy and efficiency for quantum photonics applications, including discrimination between Poissonian and sub-Poissonian light sources.

Contribution

The development and characterization of a four-photon resolution PNR-SNSPD suitable for waveguide integration at 4 K, with demonstrated photon discrimination capabilities.

Findings

Achieved photon number resolution up to four photons.

Detected Poissonian light with 22.7% efficiency at 900 nm.

Successfully discriminated sub-Poissonian from Poissonian light sources.

Abstract

Photon-number resolving (PNR) single-photon detectors are of interest for a wide range of applications in the emerging field of photon based quantum technologies. Especially photonic integrated circuits will pave the way for a high complexity and ease of use of quantum photonics. Superconducting nanowire single-photon detectors (SNSPDs) are of special interest since they combine a high detection efficiency and a high timing accuracy with a high count rate and they can be configured as PNR-SNSPDs. Here, we present a PNR-SNSPD with a four photon resolution suitable for waveguide integration operating at a temperature of 4 K. A high statistical accuracy for the photon number is achieved for a Poissonian light source at a photon flux below 5 photons/pulse with a detection efficiency of 22.7 +- 3.0% at 900 nm and a pulse rate frequency of 76 MHz. We demonstrate the ability of such a detector to discriminate a sub-Poissonian from a Poissonian light source.