First-principle description for the high-harmonic generation in a diamond by intense short laser pulse

We present a first-principles description for the electron excitation and the high-harmonic generation (HHG) in a diamond by intense laser pulse irradiation and their laser parameter dependence. Above band gap harmonics are generated after the peak of the incident laser pulse and have duration much shorter than the laser pulse. The intensity of individual harmonic peaks increases as laser intensity increases nonlinearly, and we find the blue shift of the HHG spectrum when the optical breakdown occurs. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4716192]