Time-Resolved Scanning Electron Microscopy

摘要

The project explores the combination of ultrashort pulsed laser technology with electron microscopy. The objective is to build an electron microscope with a pulsed electron beam, in order to observe nanoscale structures with ultrafast time-resolution. The pulsed electron beam is obtained by rapidly switching the electron emission of a field emission tip using the AC electric field arising from exposure to the intense electromagnetic radiation emanating from an ultrashort pulsed laser. Space-charge interactions between electrons within the electron beam are minimized by constraining the number of electrons per pulse to less than about 10. The following operating parameters are targeted: Spatial resolution: 2 nm; Temporal resolution: 3 ps Ultrafast- pulsed electron microscopy could open up the wide and important field of dynamical processes in materials that are of nanotechnological importance.