Optics Communications ( IF 2.125 ) Pub Date : 2019-12-31 , DOI: 10.1016/j.optcom.2019.125216 Jun Wang, Aihua Liu, Kai-Jun Yuan
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 H 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.