In quantum information science and quantum detection fields, single-photon detectors are widely used. They play a vital role in several scientific breakthroughs and necessary quantum optics tests. The best way to measure light is with photon number revolving detectors, but only a select few detectors can do this at low photon levels.

A new study from Yale scientists reports an on-chip detector that can resolve up to 100 photons by spatiotemporally multiplexing an array of superconducting nanowires along a single optical waveguide.

Photon-number-resolving (PNR) detectors are considered the most desirable technology for detecting light. Thanks to their exceptionally high sensitivity, they can count the photons even in the weakest light pulses. They are fundamental to several quantum applications, including quantum computing, cryptography, and remote sensing. The number of photons that current photon counting systems can detect simultaneously is limited, usually only one at a time and no more than ten.

Yiyu Zhou, a postdoctoral fellow in Tang’s lab, said: “The problem is if you have more than one, the detector becomes saturated.”

“The device not only improves PNR capacity by up to 100, but also improves count speed by three orders of magnitude. It also works at an easily accessible temperature.”

Tang said, “As a result, the device enables a wider range of applications, especially in many rapidly emerging quantum applications, such as large-scale Boson sampling, photonic quantum computing and quantum metrology.”

Credit: Yale University

Scientists also plan to integrate the detector with on-chip quantum light sources. Conventional detectors are designed to be coupled to an optical fiber, which can lead to signal loss.

Risheng Cheng, a former postdoctoral fellow in Tang’s lab and a research scientist at Meta, said: “If we could integrate everything, we would have lower loss and higher measurement reliability.”

Magazine reference:

  1. Cheng, R., Zhou, Y., Wang, S. et al. A 100-pixel photon number-resolving detector revealing photon statistics. Wet. Photon. (2022). DOI: 10.1038/s41566-022-01119-3