High-order harmonic generation in aligned molecules by combination of weak XUV and intense IR laser pulses

Abstract

We present the response of the electron to a weak XUV pulse in the presence of an intense IR 800 nm laser field. Simulations are performed on an aligned molecular ion H2+ by numerically solving the corresponding time-dependent Schrödinger equation. It is found that high order harmonic generation (HHG) spectra exhibit signature of harmonic humps, which is shown to be sensitive to the XUV pulse polarization and frequency, and the time delay between the two pulses. Harmonic humps correspond to the perturbative XUV absorption. The enhancement of harmonic humps in IR fields allows to control electron dynamics by XUV-IR combined fields in HHG processes.