Seeing Atoms and Electrons in Space and Time

Almost any activity and change in the world around us is on a fundamental level defined by the motion of atoms and electrons from initial to final conformations. If light interacts with matter, the relevant dimensions are attoseconds in time (the optical cycle) and picometers in space (atomic and electronic displacements). A movie-like visualization of structural dynamics with sufficient space-time resolution can therefore almost directly provide the atomistic mechanisms of complex macroscopic phenomena. In this presen-tation, I will give a brief account of our recent progress towards reaching this regime of 4D imaging in an experiment, and also discuss some first results and discoveries. Our unique approach for a direct, real-space visualization of electronic and nuclear motion is pump-probe electron diffraction and microscopy with optical-cycle-controlled single-electron wavepackets. We achieve simultaneously sub-atomic and sub-light-cycle reso-lution, which allows the attosecond-angstrom visualization of almost any light-matter in-teraction or transport phenomenon on fundamental length and time scales. Results on strongly correlated materials, metamaterials, graphene and attosecond dynamics in sili-con indicate the applicability of our approaches to diverse phenomena in different mate-rials. We are currently adopting a commercial electron microscope to attosecond resolu-tion, in order to study fundamental dynamics in complex materials of almost arbitrary complexity and shape.