Attosecond chronoscopy of electron scattering in dielectric nanoparticles

The scattering of electrons in dielectric materials is central to laser nanomachining(1), light-driven electronics(2) and radiation damage(3-5). Here, we demonstrate real-time access to electron scattering by implementing attosecond streaking spectroscopy on dielectric nanoparticles: photoelectrons are generated inside the nanoparticles and both their transport through the material and photoemission are tracked on an attosecond timescale. We develop a theoretical framework for attosecond streaking spectroscopy in dielectrics and identify that the presence of the internal field inside the material cancels the influence of elastic scattering, enabling the selective characterization of the inelastic scattering time. The approach is demonstrated on silica nanoparticles, where an inelastic mean-free path is extracted for 20-30 eV. Our approach enables the characterization of inelastic scattering in various dielectric solids and liquids, including water, which can be studied in the form of droplets.