High-order harmonic generation of benzene molecules irradiated by circularly polarized laser pulses

Abstract

High-order harmonic generation is investigated by using time-dependent density functional theory to numerically simulate the interaction of the benzene molecule with a few-cycle circularly polarized laser pulse. Compared with the harmonics from atoms and diatomic molecules with similar ionization energy irradiated by the same laser pulse, the harmonics from benzene molecules possess higher efficiency and cut-off energy. Further research reveals that the harmonic efficiency and cut-off energy of the benzene molecule increase gradually as the wavelength of the driving laser decreases. Through the analysis of the time-dependent evolution of electronic wave packets, it is found that the harmonic generation can be attributed to the recombination of the ionized electrons and their parent ions. By optimizing the driving laser pulse, we demonstrated that high-order harmonic generation in the benzene molecule can be used to produce isolated circularly polarized attosecond pulse.