Tungsten Germanide Single-Photon Detectors with Saturated Internal Detection Efficiency at Wavelengths up to 29 {\mu}m

TL;DR

This paper reports on tungsten germanide superconducting nanowire single-photon detectors that achieve saturated internal detection efficiency at wavelengths up to 29 micrometers, enabling scalable mid-infrared photon detection for various scientific applications.

Contribution

Introduction of tungsten germanide SNSPDs with high infrared sensitivity and scalability, achieving saturated efficiency at unprecedented mid-infrared wavelengths.

Findings

Saturated detection efficiency at wavelengths up to 29 μm.

Compatibility of tungsten germanide with large-scale fabrication.

Potential applications in astrophysics and molecular spectroscopy.

Abstract

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 $\mathrm{\mu m}$. 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.