Control of long electron quantum paths in high-order harmonic generation by phase-stabilized light pulses

In this work we report on the first experimental demonstration of selection of the long electron quantum paths in the process of high-order harmonic generation by phase-stabilized multiple-cycle light pulses. A complete experimental investigation of the role of intensity and carrier-envelope phase of the driving pulses on the spectral characteristics of the long quantum paths is performed. Simulations based on the nonadiabatic saddle-point method and on a complete nonadiabatic three-dimensional model reproduce the main features of the experimental results. The use of phase-stabilized driving pulses allows one to control, on an attosecond temporal scale, the spectral and temporal characteristics associated with the electron quantum paths involved in the harmonic generation process.