微弱な光子を検出する量子技術を大型化（NIST Researchers Supersize Quantum Technology to Help Detect Faint Photons）

2026-08-24 米国国立標準技術研究所（NIST）

NIST（米国国立標準技術研究所）の研究チームは、微弱な光子を高感度に検出するため、量子技術を従来より大幅に大型化する新しい方式を開発した。研究では、超伝導ナノワイヤを利用した単一光子検出器（SNSPD）の構造を拡張し、検出領域を大きくしながら高い検出性能を維持することに成功した。従来のSNSPDは極めて高感度である一方、検出可能な領域が小さいため、光を正確に集光する必要があった。新方式では、より大きな検出器を実現することで、光子を取り込む光学系の制約を緩和し、量子通信、宇宙観測、暗い天体からの微弱光検出などへの応用可能性を広げる。研究は、量子光学デバイスを実用的な大規模システムへ拡張する上で重要な進展となる。

In this illustration, photons hit a strip of superconducting wire, disrupting the electric current and registering an electric pulse. Each pulse tells researchers about the light that has hit the detector, which is beneficial for applications like biomedical imaging and astronomy.Credit: Natasha Hanacek/NIST

＜関連情報＞

最大0.1mm幅の超伝導ナノワイヤ単一光子検出器の本来の性能限界に到達 Reaching the intrinsic performance limits of superconducting nanowire single-photon detectors up to 0.1 mm wide

Kristen M. Parzuchowski, Eli Mueller, Bakhrom G. Oripov, Benedikt Hampel, Ravin A. Chowdhury, Sahil R. Patel, Daniel Kuznesof, Emma K. Batson, Ryan Morgenstern, Robert H. Hadfield, Varun B. Verma, Matthew D. Shaw, Jason P. Allmaras, Martin J. Stevens, Alex Gurevich, and Adam N. McCaughan
Optica Published: August 19, 2026
DOI:https://doi.org/10.1364/OPTICA.599984

Abstract

Superconducting nanowire single-photon detectors combine high detection efficiency, low noise, and excellent timing resolution, making them a leading platform for photon-counting applications. However, despite decades of materials and fabrication research, detector performance has never been shown to match theoretical performance expectations. Here, we demonstrate in situ tuning of a detector from its typical, suboptimal operation, to a regime limited only by material quality, allowing the device to reach its intrinsic performance limit. Our approach is based on current-biased superconducting “rails” placed on either side of the detector that redistribute current across its width to achieve peak performance. This technique reduces the dark count rate by 10 orders of magnitude. Further, we show operation at this intrinsic performance limit for devices up to 0.1 mm wide and also demonstrate near-unity internal detection efficiency at a wavelength of 4 µm for a 20 µm wide detector—a factor of 20 wider than the current state of the art. This work enables future detectors to overcome the Pearl limit for device width, paving the way for arbitrarily large detectors.