Superconducting nanowire photon number resolving detector at telecom wavelength

TL;DR

This paper presents a superconducting nanowire detector capable of resolving up to four photons at telecom wavelengths, with high sensitivity, low dark counts, and fast counting, advancing quantum optics and communication technologies.

Contribution

The paper introduces a novel superconducting nanowire photon number resolving detector that can count multiple photons simultaneously at telecom wavelengths, with improved performance metrics.

Findings

Capable of resolving up to 4 photons simultaneously.

Features ultralow dark count rate and high counting frequency.

Operates effectively at telecom wavelengths.

Abstract

The optical-to-electrical conversion, which is the basis of optical detectors, can be linear or nonlinear. When high sensitivities are needed single-photon detectors (SPDs) are used, which operate in a strongly nonlinear mode, their response being independent of the photon number. Nevertheless, photon-number resolving (PNR) detectors are needed, particularly in quantum optics, where n-photon states are routinely produced. In quantum communication, the PNR functionality is key to many protocols for establishing, swapping and measuring entanglement, and can be used to detect photon-number-splitting attacks. A linear detector with single-photon sensitivity can also be used for measuring a temporal waveform at extremely low light levels, e.g. in long-distance optical communications, fluorescence spectroscopy, optical time-domain reflectometry. We demonstrate here a PNR detector based on parallel superconducting nanowires and capable of counting up to 4 photons at telecommunication wavelengths, with ultralow dark count rate and high counting frequency.