Colangelo, Marco and Walter, Alexander B. and Korzh, Boris A. and Schmidt, Ekkehart and Bumble, Bruce and Lita, Adriana E. and Beyer, Andrew D. and Allmaras, Jason P. and Briggs, Ryan M. and Kozorezov, Alexander G. and Wollman, Emma E. and Shaw, Matthew D. and Berggren, Karl K. (2022) Large-Area Superconducting Nanowire Single-Photon Detectors for Operation at Wavelengths up to 7.4 μm. Nano Letters, 22 (14). pp. 5667-5673. ISSN 1530-6984
Full text not available from this repository.Abstract
The optimization of superconducting thin-films has pushed the sensitivity of superconducting nanowire single-photon detectors (SNSPDs) to the mid-infrared (mid-IR). Earlier demonstrations have shown that straight tungsten silicide nanowires can achieve unity internal detection efficiency (IDE) up to λ = 10 μm. For a high system detection efficiency (SDE), the active area needs to be increased, but material nonuniformity and nanofabrication-induced constrictions make mid-IR large-area meanders challenging to yield. In this work, we improve the sensitivity of superconducting materials and optimize a high-resolution nanofabrication process to demonstrate large-area SNSPDs with unity IDE at 7.4 μm. Our approach yields large-area meanders down to 50 nm width, with average line-width roughness below 10%, and with a lower impact from constrictions compared to previous demonstrations. Our methods pave the way to high-efficiency SNSPDs in the mid-IR band with potential impacts on astronomy, imaging, and physical chemistry.