Influence of coherent vibrational excitation on the high-order harmonic generation of diatomic molecules

Abstract

High-order harmonic generation (HHG) in atomic systems by the highly nonlinear response to an intense laser field is a prominent pathway to the synthesis of ever shorter laser pulses at increasingly higher photon energies. Extensions of this process to molecules add to the complexity but also offer novel opportunities as multicenter effects and the coupling to nuclear degrees of freedom can influence HHG. In this paper, we theoretically explore the impact of coherent vibrational excitations of diatomic molecules on the HHG spectrum within the framework of time-dependent density-functional theory. We observe the appearance of interference structures in the HHG spectra controlled by resonances between the driving field and the vibrational wave packet.