Theory of high-harmonic generation in solids

Abstract

High-harmonic generation (HHG) in bulk crystals exposed to intense mid-infrared lasers with photon energies below the bandgap is investigated theoretically. A three dimensional, two-band model that considers both interband and intraband currents is used. It is shown that the interband current is the dominant mechanism for HHG in solids. A physical interpretation of interband HHG-similar to atomic HHG-is provided by saddle point analysis. The effects of dephasing time and driving field wavelength on the harmonic specrum are investigated.