4D Near-Field Electron Tomography

New techniques for imaging electromagnetic near-fields have great importance in life science, material science, and nanotechnology [1]. Prominently, ultrafast imaging in electron microscopy has seen a surge of interest with the development of photon-induced near-field electron microscopy (PINEM) [2]. This capability and its generalizations [3], [4] provide unprecedented spatio-temporal resolutions, applicable to broad regimes of the electromagnetic spectrum, from THz [3] to optical [2] frequencies. However, all works so far only provided a 2D projection of the near-field, limited by the direction of motion of the electron passing through the sample.