Abstract

High-order harmonic spectroscopy combines attosecond temporal with Ångstrom spatial resolution, and therefore features unique properties for studying light-matter interaction. The underlying process of HHG can be described by the three-step model [1], consisting of tunnel ionization, excursion in the continuum and recombination. While the tunnel ionization and the recombination are well studied [2–4], the electron’s excursion in the continuum is not. Measurements of the dissociation process in molecules indicate a strong sensitivity of the amplitude of the emitted harmonic radiation on the presence of neighboring atoms within the range of the electronic excursion [5]. We explore this sensitivity by increasing the target density, and thus reducing the mean inter-particle distance to values where the distance between a neighboring molecule and a parent ion matches the maximum electronic displacement. The induced possibility for a perturbation to the quantum path leads to a suppression of the recombination step. This method gives access to measure the maximum electronic displacement.

© 2015 IEEE