100 kframe/s 8 bit monolithic single-photon imagers

We present an array detector of a column of 32 smart pixels, each comprising a 20-mum single-photon avalanche diode, a front-end electronics for quenching the avalanche and resetting the detector after each ignition, an 8 bit photon counter and a storing register. Each pixel has a dark-counting rate of 2 kcps (counts per second) and can reach a maximum photon rate of 25 Mcps. The image is acquired by counting photons within programmable frame times, down to 320 ns. The maximum frame rate tops from 100 kframe/s to 3 Mframe/s, depending on the desired dynamic range, from 8 to 3 bits respectively. We report on the design and characterization of the chip and we ascertain the expandability of the array to a larger number of columns for high-frame rate two-dimensional single-photon imagers.