Superconducting nanowire single-photon detectors (SNSPDs) are among the most sensitive single-photon detectors available and have the potential to transform fields ranging from infrared astrophysics to molecular spectroscopy. However, extending their performance into the mid-infrared spectral region - crucial for applications such as exoplanet transit spectroscopy and vibrational fingerprinting of molecules - has remained a major challenge, primarily due to material limitations and scalability constraints. Here, we report on the development of SNSPDs based on tungsten germanide, a novel material system that combines high infrared sensitivity with compatibility for large-scale fabrication. Our detectors exhibit saturated internal detection efficiency at wavelengths up to 29 μm. This advance enables scalable, high-performance single-photon detection in a spectral region that was previously inaccessible, opening new frontiers in remote sensing, thermal imaging, environmental monitoring, molecular physics, and astronomy.
@article{arxiv.2511.20868,
title = {Tungsten Germanide Single-Photon Detectors with Saturated Internal Detection Efficiency at Wavelengths up to 29 {\mu}m},
author = {Benedikt Hampel and Daniel Kuznesof and Andrew S. Mueller and Sahil R. Patel and Robert H. Hadfield and Emma E. Wollman and Matthew D. Shaw and Dirk Schwarzer and Alec M. Wodtke and Khalid Hossain and Allison V. Mis and Alexana Roshko and Richard P. Mirin and Sae Woo Nam and Varun B. Verma},
journal= {arXiv preprint arXiv:2511.20868},
year = {2025}
}