High harmonic generation in fullerene molecules

TL;DR

This study investigates high-harmonic generation in fullerene molecules C$_{60}$ and C$_{70}$ using dynamical Hartree-Fock theory, revealing multiple harmonic plateaus, dependence on field strength, and differences between the molecules.

Contribution

It provides the first detailed analysis of HHG in fullerenes considering electron-electron interactions and field effects, highlighting differences between C$_{60}$ and C$_{70}$.

Findings

Multiple harmonic plateaus scale linearly with field strength.

Increasing photon energy extends the harmonic cutoff.

C$_{70}$ exhibits richer spectra and higher intensity than C$_{60}$.

Abstract

Using dynamical Hartree-Fock mean-field theory, we study the high-harmonic generation (HHG) in the fullerene molecules C$_{60}$ and C$_{70}$ under strong pump wave driving. We consider a strong-field regime and show that the output harmonic radiation exhibits multiple plateaus, whose borders are defined by the molecular excitonic lines and cutoff energies within each plateau scale linearly with the field strength amplitude. In contrast to atomic cases for the fullerene molecule, with the increase of the pump wave photon energy the cutoff harmonic energy is increased. We also show that with the increase of the electron-electron interaction energy overall the HHG rate is suppressed. We demonstrate that the C$_{70}$ molecule shows richer HHG spectra and a stronger high-harmonic intensity than the C$_{60}$.