Large Array of Single-Photon Counting Quantum Capacitance Detectors

The quantum capacitance detector (QCD) is a high-sensitivity direct detector under development for low background applications such as far-infrared (IR) spectroscopy from a cold space telescope. The QCD has demonstrated an optically-measured noise equivalent power of 2
$ \times $
10
⁻²⁰
W
$ \cdot $
Hz
^−1/2
at 1.5 THz, making it among the most sensitive far-IR detectors systems ever demonstrated, and meeting the requirements for spaceborne spectroscopy. The device is also intrinsically fast and, thus, is able to count individual far-IR photons. Here, we report a new 2-D array yielding 291 QCDs out of 441 pixels patterned, demonstrating photon counting in a large scale. A readout technique was developed to reveal the presence or absence of a photon within a frame by a single number, providing a way to scale up to even larger arrays while maintaining a modest data rate need.