Tracing electron in motion: From atoms to solids

With the fastest optical and soft x-ray fields as a part of its repertoire, attosecond physics has opened up new avenues for exploring ultrafast electronic processes in atoms, molecules, surfaces or nanostructures. I will discuss how attosecond optical synthesis of light allows, the exploration and control of fundamental electronic phenomena in condensed matter. Electron motion in bulk media, driven by intense, precisely-sculpted, optical fields gives rise to controllable electric currents, the frequency of which extends to the multi-ten-Petahertz range, advancing lightwave electronics to new realms of speed and precision. Coherent extreme ultraviolet radiation emerging in these coherent charge oscillations offers direct insight into structural and dynamical properties of the underlying medium, previously inaccessible to conventional solid-state spectroscopies. By endowing essential x-ray spectroscopies of solids with attosecond temporal resolution, optical half-opt ical cycle fields, combined with extreme ultraviolet pulses, offer, for the first time, access into the attosecond dephasing of electronic excitation of highly-correlated, condensed phase electronic systems. We anticipate these new capabilities to result in far reaching implications in fundamental and applied, electronic and photonic sciences.