Sounds like MKIDs - microwave kinetic inductance detectors. They're arrays of little LC oscillators where the inductance changes when a photon hits. They can ac

Sounds like MKIDs - microwave kinetic inductance detectors. They're arrays of little LC oscillators where the inductance changes when a photon hits. They can actually resolve frequency and time of arrival of a photon, which is super useful, especially for photon-limited astrometry. [0] [1] [0] - https://wikipedia.org/wiki/Kinetic_inductance_detector https://wikipedia.org/wiki/Kinetic_inductance_detector [1] - https://web.physics.ucsb.edu/~bmazin/mkids.html https://web.physics.ucsb.edu/~bmazin/mkids.html