Time- and number-resolved photon detection is crucial for photonic quantum information processing. Existing photon-number-resolving (PNR) detectors usually have limited timing and dark-count performance or require complex fabrication and operation. Here we demonstrate a PNR detector at telecommunication wavelengths based on a single superconducting nanowire with an integrated impedance-matching taper. The prototyping device was able to resolve up to five absorbed photons and had 16.1 ps timing jitter, <2 c.p.s. device dark count rate, ∼86 ns reset time, and 5.6% system detection efficiency (without cavity) at 1550 nm. Its exceptional distinction between single- and two-photon responses is ideal for coincidence counting and allowed us to directly observe bunching of photon pairs from a single output port of a Hong-Ou-Mandel interferometer. This detector architecture may provide a practical solution to applications that require high timing resolution and few-photon discrimination.
@article{arxiv.1911.09485,
title = {Resolving photon numbers using a superconducting tapered nanowire detector},
author = {Di Zhu and Marco Colangelo and Changchen Chen and Boris A. Korzh and Franco N. C. Wong and Matthew D. Shaw and Karl K. Berggren},
journal= {arXiv preprint arXiv:1911.09485},
year = {2020}
}