Phase difference effect on high-order harmonic generation of crystals driven by two-color laser pulses

We investigate the characteristics of the high-order harmonics generation (HHG) emitted from one-dimension crystals driven by the two-color combined field pulse based on the numerical solution of the time-dependent Schroedinger equation of the crystal in the two-color laser fields (fundamental frequency field and double frequency field). We find that the strength of the second plateau of HHG is significantly enhanced, and changed with the phase difference of the double-color fields. Furthermore, when the other parameters of the two-color laser pulse remain unchanged, the HHG yield of crystals in the second plateau can be enhanced effectively by adjusting the phase difference of the two-color laser pulse, and the enhancement of HHG yield varies with the width of the laser pulses. (authors)