Strong-field-driven dynamics and high-harmonic generation in interacting 1D systems

We explore the role of electronic band structure and Coulomb interactions in solid-state HHG by studying the optical response of linear atomic chains and carbon nanotubes to intense ultrashort pulses. Specifically, we simulate electron dynamics by solving self-consistently the single-particle density matrix equation of motion in the presence of intense ultrafast optical fields and electron interactions. Our 1D model provides insight on the temporal evolution of electronic states in reciprocal space. We demonstrate that electron interactions play an important role in the HHG yield. This model further predicts that doped semiconductors generate high harmonics more efficiently than their metallic and undoped counterparts. To complement this idealized system we also show results for HHG in more realistic quasi-1D structures such as carbon nanotubes, whose behavior is found to be in good qualitative agreement with that of the atomic chains. Our findings apply directly to extreme nonlinear optical phenomena and can be extended to optimize existing platforms for HHG or identify new solid-state alternatives in the context of nonlinear plasmonics.