Overcoming the shot-noise limitation of three-dimensional active imaging

Depth resolution is limited by the photoelectron shot noise in conventional gain-modulated active three-dimensional (3D) imaging methods. A proposed method, which is based on photon intensity correlation, is presented to overcome the depth resolution limitation. The signal photons are amplified by an imaging intensifier, and are then divided into two beams by a beam splitter. The theory shows that the shot-noise limitation is broken using the strong intensity coherence between the two beams. The experiment results show that the depth resolution of the correlated active 3D imaging method is three times better than that of the shot-noise limitation.