Final Report Summary - 4D IMAGING (Towards 4D Imaging of Fundamental Processes on the Atomic and Sub-Atomic Scale) All matter around us consists of electrons and atoms. Their linkage and motion determines the outcome of almost any light-matter interaction. This project has established the essential concepts for combining electron microscopy/diffraction with its atomic resolution in space with the methods of attosecond laser spectroscopy with its sub-light-cycle temporal resolution. Laser-generated single-electron wave packets do not repel themselves via space charge forces and can therefore be compressed in time almost arbitrarily, while maintaining their sub-atomic de Broglie wavelength and atomic-resolution capability in diffraction. This now allows imaging fundamental atomic and electronic activities directly in their natural state of motion.
