Enhanced Mid-Infrared Single-Photon Detection with Antenna-Coupled Superconducting Nanowires

Area of Science:

• Quantum Optics
• Materials Science
• Nanotechnology

Background:

• Superconducting nanowire single-photon detectors (SNSPDs) traditionally increase detection area via nanowire meandering.
• Longer nanowires suffer from material inhomogeneities and fabrication defects, reducing efficiency and increasing dark counts.
• Scaling SNSPDs to sub-100 nm widths and sub-5 nm thicknesses for infrared detection exacerbates these trade-offs.

Purpose of the Study:

• To demonstrate an antenna-coupled SNSPD architecture for enhanced effective photon-detection area.
• To overcome the limitations of nanowire meandering in scaling SNSPD detection area.
• To improve SNSPD performance for mid- to far-infrared applications.

Main Methods:

• Integration of a crossed bowtie antenna with a narrow (80 nm) and thin (3 nm) WSi nanowire.
• Fabrication of antenna-coupled SNSPDs.
• Characterization of effective detection area, internal detection efficiency, and dark-count rates at 7.4 μm.

Main Results:

• A 15.7× increase in effective detection area at 7.4 μm was achieved using the antenna-coupled SNSPD compared to a bare nanowire.
• The antenna coupling maintained the same internal detection efficiency and dark-count rate as the bare nanowire.
• The proposed architecture enhances effective detection area without increasing nanowire length.

Conclusions:

• Antenna coupling offers a scalable method to increase the effective photon-detection area of SNSPDs.
• This approach reduces noise-equivalent power, enhancing SNSPD performance.
• The technology holds promise for applications in astronomy, biological imaging, and molecular spectroscopy.