Abstract
An option to overcome the limits of electronics are excitons, quasi-particles generated by the electron-hole Coulomb interaction. A fundamental prerequisite is the possibility to control their properties with optical fields. We adopted attosecond reflection spectroscopy to investigate the interplay between core excitons and ultrashort infrared pulses in MgF2. Their ultrafast response is divided into two contributions, unfolding on different time scales, related to the exciton dual nature. Namely, we discern the atomic-like behaviour, dominating the few-femtosecond response, from the excitonic solid-like characteristics, with sub-femtosecond timing. Theoretical models highlight the role of the exciton binding energy in dictating their optical response.
