Superconducting microwire detectors based on WSi with single-photon sensitivity in the near-infrared
Jeff Chiles, Sonia Buckley, Adriana Lita, Varun Verma, Jason P. Allmaras, Boris Korzh, Matthew D. Shaw, Jeffrey M. Shainline, Richard P. Mirin, S. W. Nam
Abstract
We report on the fabrication and characterization of single-photon-sensitive WSi superconducting detectors with wire widths from 1 μm to 3 μm. The devices achieve the saturated internal detection efficiency at a wavelength of 1.55 μm and exhibit maximum count rates in excess of 105 s−1. We also investigate the material properties of the silicon-rich WSi films used for these devices. We find that many devices with active lengths of several hundred micrometers exhibit critical currents in excess of 50% of the depairing current. A meandered detector with a 2.0 μm wire width is demonstrated over a surface area of 362 × 362 μm2, showcasing the material and device quality achieved.