Attosecond microscopy —Advances and outlook

Abstract Attosecond microscopy aims to record electron movement on its natural length and time scale. It is a gateway to understanding the interaction of matter and light, the coupling between excitations in solids, and the resulting energy flow and decoherence behavior, but it demands simultaneous temporal and spatial resolution. Modern science has conquered these scales independently, with ultrafast light sources providing sub-femtosecond pulses and advanced microscopes achieving sub-nanometer resolving power. In this perspective, we inspect the challenges raised by combining extreme temporal and spatial resolution and then highlight how upcoming experimental techniques overcome them to realize laboratory-scale attosecond microscopes. Referencing proof-of-principle experiments, we delineate the techniques’ strengths and their applicability to observing various ultrafast phenomena, materials, and sample geometries.