Temporal array with superconducting nanowire single-photon detectors for photon-number-resolution

TL;DR

This paper demonstrates a 16-element temporal-array photon-number-resolving detector using superconducting nanowire single-photon detectors, capable of resolving photon numbers from 10^-3 to 10^2, with potential improvements using higher efficiency SNSPDs.

Contribution

The paper introduces a novel 16-element temporal-array PNR detector and experimentally verifies its photon-number resolution capabilities compared to single-photon detectors.

Findings

Can resolve photon numbers from 10^-3 to 10^2

Array detector outperforms single-photon detectors in photon-number resolution

Effective quantum efficiency of 49% limits single-shot measurement precision

Abstract

We present an experimental realization of a 16 element, temporal-array, photon-number-resolving (PNR) detector, which is a multiplexed single-photon detector that splits an input signal over multiple time-bins, and the time-bins are detected using two superconducting nanowire single-photon detectors (SNSPD). A theoretical investigation of the PNR capabilities of the detector is performed and it is concluded that compared to a single-photon detector, our array detector can resolve one order of magnitude higher mean photon numbers, given the same number of input pulses to measure. This claim is experimentally verified and we show that the detector can accurately predict photon numbers between $10^{-3}$ to $10^{2}$. Our present detector is incapable of single-shot photon-number measurements with high precision since its effective quantum efficiency is $49\,\%$. Using SNSPDs with a higher quantum efficiency the PNR performance will improve, but the photon-number resolution will still be limited by the array size.