Far-IR/submm array of multiplexed Single Photon Detectors based on the Quantum Capacitance Detector

We will develop a 500-pixel array of quantum capacitance detectors which have 1) per-pixel noise equivalent power (NEP) below 3e-20 W/sqrt(Hz), 2) high absorption efficiency, and 3) sufficient speed of response to count individual mid-IR through far-IR photons at rates up to 10 kHz. The full array will be read out with a single microwave circuit using a suite of probe tones interacting with resonators. The sensitivity, speed, and MUXing are the key enabling requirements for moderate-resolution (R~500) zodi-limited spectroscopy on future cryogenic far-IR facilities such as the Origins Space Telescope (formerly Far-IR Surveyor) or a far-IR probe-class mission. The photon counting capability offers the potential for enhanced scientific performance for a) high-stability applications such as exoplanet spectroscopy and b) high-resolution direct-detection spectroscopy at the shot-noise limit. Our work builds on the success with few-pixel quantum capacitance demonstrations at 200 microns, but we require a dedicated multi-pixel readout architecture, absorber and backshort geometry adapted to shorter wavelengths (down to 30 microns with a goal of 6 for exoplanet photon counting), and demonstration of high yield (>75%) with an improved tunnel junction design and fabrication approach.