Quantum detector tomography of a high dynamic-range superconducting nanowire single-photon detector

TL;DR

This paper presents quantum detector tomography of a superconducting nanowire single-photon detector capable of measuring up to 71000 photons per pulse, demonstrating a comprehensive quantum description across its entire dynamic range.

Contribution

It introduces a multiplexing scheme for quantum detector tomography of SNSPDs, enabling accurate POVM reconstruction over a large dynamic range.

Findings

Successfully reconstructed POVMs spanning the detector's full dynamic range

Verified the quantum model by measuring the mean photon number of bright states

Demonstrated reliable quantum description of large-scale SNSPDs

Abstract

We demonstrate and verify quantum detector tomography of a superconducting nanowire single-photon detector (SNSPD) in a multiplexing scheme which permits measurement of up to 71000 photons per input pulse. We reconstruct the positive operator valued measure (POVM) of this device in the low photon-number regime, and use the extracted parameters to show the POVMs spanning the whole dynamic range of the device. We verify this by finding the mean photon number of a bright state. Our work shows that a reliable quantum description of large-scale SNSPD devices is possible, and should be applicable to other multiplexing configurations.