Patent ID: 8558234

Claim:
A photodetector comprising: a photocathode formed of a non-cesiated, semiconductor material, said photocathode having an activation layer that has one of either a piezoelectrically induced polarization field or a delta-doped surface, such that where at least one photon within a selected wavelength range impinges on said photocathode at least one electron is emitted from the surface of said photocathode; a thinned delta-doped imager array, said imager array being disposed across an accelerating gap from said photocathode; an electric field generator for generating an electric field across said accelerating gap, said electrical field generator being disposed in relation to said imager array and said photocathode such that the electric field accelerates said at least one electron across said accelerating gap to impinge on said imager array; and wherein the accelerating gap is sufficiently small such that the electrons produced from said photocathode are proximity focused onto said imager array such that a plurality of electrons are generated from each of the accelerated electrons that impinge thereon, and wherein only a single electron is generated for photons that impinge directly thereon.