Spatial Imaging via Photon Arrival Time

In OPN’s December “Optics in 2020” review of interesting research, Alex Turpin and colleagues reported on work in which a single-point, single-photon avalanche diode (SPAD) is used to provide a spatial image of a scene—without any actual spatial sensing. Instead, the scene is flood-illuminated with a pulsed laser, the return light is focused with the SPAD, and the arrival time of the photons from the whole scene, coupled with an AI algorithm, is used to form a 3D estimate of the scene.