  A large-format mid-infrared single-photon imager with very low dark count
rates would enable a broad range of applications in fields like astronomy and
chemistry. Superconducting nanowire single-photon detectors (SNSPDs) are a
mature photon-counting technology as demonstrated by their figures of merit.
However, scaling SNSPDs to large array sizes for mid-infrared applications
requires sophisticated readout architectures in addition to superconducting
materials development. In this work, an SNSPD array design that combines a
thermally coupled row-column multiplexing architecture with a thermally coupled
time-of-flight transmission line was developed for mid-infrared applications.
The design requires only six cables and can be scaled to larger array sizes.
The demonstration of a 64-pixel array shows promising results for wavelengths
between $\mathrm{3.4\,\mu m}$ and $\mathrm{10\,\mu m}$, which will enable the
use of this single-photon detector technology for a broad range of new
applications.
