Enhancing image contrast and slicing electron pulses in 4D near field electron microscopy

In this Letter, we discuss the use of photon-induced near field electron microscopy (PINEM) to reach new limits of temporal and spatial resolutions. We invoke two optical femtosecond pulses, one of them is for the usual clocking of dynamical change but the second one is for gating (slicing) the imaging-electron continuous or pulsed beam. It is shown that in both cases the resolution becomes that of the optical gating pulse and not of the electron one. We also show that by using the near field of a nanoparticle it is possible to enhance contrast in imaging of materials and including biological structures.