Interaction of ultrashort laser pulses with condensed matter: Dielectrics and nanotips

The non-linear response of matter to ultrashort laser pulses on the (sub)femtosecond scale allows controlling and steering electronic motion. Strong field interaction with condensed matter promises to eventually realize the dream of light-field electronics with devices operating on the femto-second time scale and nanometer length scale. Theoretical exploration of such processes faces the challenge to simulate the time-dependent many-electron problem. In this talk we illustrate recent progress with the help of two examples: electron emission from nanoscale metallic tips exploring near-field enhancement and rescattering and the femtosecond-scale transition from an isolating to a metallic state of a bulk dielectric, SiO₂.