Quantum detector tomography of superconducting nanostrip photon-number-resolving detector

TL;DR

This paper enhances the photon-number-resolving capabilities of superconducting nanostrip detectors using waveform pattern matching and performs quantum detector tomography to characterize its performance, achieving resolution up to five photons.

Contribution

It introduces a method to improve photon-number resolution and provides a quantum detector tomography analysis of the superconducting nanostrip detector.

Findings

Photon-number resolution up to five photons without multiplexing.

Improved performance for high-average photon number light.

Quantum detector tomography confirms the detector's capabilities.

Abstract

Superconducting nanostrip photon detectors have been used as single photon detectors, which can discriminate only photons' presence or absence. It has recently been found that they can discriminate the number of photons by analyzing the output signal waveform, and they are expected to be used in various fields, especially in optical quantum information processing. Here, we improve the photon-number-resolving performance for light with a high-average photon number by pattern matching of the output signal waveform. Furthermore, we estimate the positive-operator-valued measure of the detector by a quantum detector tomography. The result shows that the device has photon-number-resolving performance up to five photons without any multiplexing or arraying, indicating that it is useful as a photon-number-resolving detector.