Interference of harmonics emitted by different tunneling momentum channels in laser fields

Abstract

Abstract By numerically solving the semiconductor Bloch equation (SBEs), we theoretically study the highharmonic generation of ZnO crystals driven by one-color and two-color intense laser pulses. The results show the enhancement of harmonics and the cut-off remains the same in the two-color field, which can be explained by the recollision trajectories and electron excitation from multi-channels. Based on the quantum path analysis, we investigate contribution of different range of the crystal momentum k of ZnO to the harmonic yield, and find that in two-color laser fields, the intensity of the harmonic yield of different range from the crystal momentum make a big difference and the harmonic intensity is depressed from all k channels, which is related to the interferences between harmonics from symmetric k channels.