Jankunas Doctoral Dissertation Award: Attosecond science with recolliding electrons

Measuring the motion of valence­shell electrons in molecules is one of the main research thrusts in modern ultrafast science. The process of high­harmonic generation (HHG), the conversion of many infrared photons into one XUV photon, relies on the laser­driven ionization, acceleration and precisely timed recombination in a strong laser field. The frequencies emitted upon recollision can be uniquely mapped to a transit time of the electron in the continuum thus providing attosecond temporal and Angstrom spatial resolution encoded in the HHG spectrum. In this talk we present experiments that utilize these capacities of HHG for following a coherent valence­shell electron current in nitric oxide on the femtosecond time scale in a classical pump­probe experiment. Furthermore, we use the intrinsic time resolution of the HHG process to measure attosecond time­scale electron dynamics: The motion of an electron hole across a molecular chain after ionization in spatially oriented iodoacetylene molecules.