A 32×32 photon counting camera

Combining spatial, timing, and single-photon resolution

Abstract

Silicon photon counting detectors have been in production for many years but until recently they were single pixel detectors that required a custom and specialized fabrication process. In the last couple of years, CMOS compatible processes were developed to produce silicon photon counting detectors with very good performances. Usually, in single photon avalanche diodes (SPADs), the electronics for quenching the diode and the electronics for picking-up the avalanche ignition are separate from the SPAD itself. Commercial detectors of such a design can have, for example, 49 % detection efficacy at 550 nm, dark counts of 1/s for an active area of 20 μm in diameter, and 30 ps timing resolution.