  Superconducting nanowire single-photon detectors (SNSPDs) with high timing
resolution and low background counts in the mid infrared (MIR) have the
potential to open up numerous opportunities in fields such as exoplanet
searches, direct dark matter detection, physical chemistry, and remote sensing.
One challenge in pushing SNSPD sensitivity to the MIR is a decrease in the
signal-to-noise ratio (SNR) of the readout signal as the critical currents
become increasingly smaller. We overcome this trade-off with a new device
architecture that employs impedance matching tapers and superconducting
nanowire avalanche photodetectors to demonstrate increased SNR while
maintaining saturated internal detection efficiency at 7.4 {\mu}m and getting
close to saturation at 10.6 {\mu}m. This work provides a novel platform for
pushing SNSPD sensitivity to longer wavelengths while improving the scalability
of the readout electronics.
