Controlling and Reading Interference Structures Created by Strong Field Ionizing Attosecond Electron Wave Packets

Abstract

We use cycle-sculpted two-color waveforms to drive electronic wavepackets generated by strong-field ionization from helium gas atoms and analyse their momentum spectra measured by electron-ion coincidence momentum spectroscopy. Varying the relative phase of the two colors allows to sculpt the ionizing field and hence to control the emission times and motion of the wavepackets on an attosecond timescale. We show that the measured electron momentum spectra contain interference patterns created by pairs of electron wavepackets that are released within a single laser-field-cycle. We experimentally distinguish these sub-cycle interference structures from above-threshold ionization (ATI) peaks and argue that they can be used to extract the sub-cycle phase-evolution of the laser-driven complex bound-state wavefunction.