Applications in Microscopy and Lithography for a Heralded Electron Source

We describe the design for a heralded electron source made from a standard electron gun, a weak photonic coupler, an electron energy filter, and a single photon detector. We define a figure of merit for the heralding efficiency which describes the sub-Poissonian statistics of the source and can be written in terms of the traditional Klyshko heralding efficiency. Using this figure of merit, we discuss the engineering requirements for efficient heralding. Finally, we discuss potential applications: dose reduction in quantitative bright field STEM and error reduction in electron lithography.