High-order harmonic generation in doped diamond: comparison of light and heavy regimes

The electronic response of crystalline n-doped diamond in light and heavy concentrations, as well as high harmonic generation following irradiation by a few cycles high-intensity laser pulse are calculated by modeling the dynamics in the framework of combined time-dependent density functional theory and virtual crystal approximation. The driver pulse frequencies are above and below the band gap frequency. The comparison of transient optoelectronic properties between two regimes shows that light doping enhances the magnitude of HHG. Further, the above gap irradiated doped diamond in both regimes represents much bright harmonics than below gap one. Modulations of the transient effective mass under irradiation of femtosecond laser are analyzed for both doping rates over the Brillouin zone. Comparison of the spectrum from virtual crystal approximation with available harmonic data of dielectric materials from real defected supercell calculations shows the important contribution of ionic relaxation in the description of nonlinear optical properties.