Quantum interferences between rescattering orbits with multiexcitation channels in the recollision excitation process of nonsequential double ionization

Abstract

Based on the strong-field approximation (SFA), we investigate the interference between different returning orbits of the rescattering electron in nonsequential double ionization. We find that the effect of interference is negligible in the recollision-impact ionization process but is prominent in the recollision excitation with subsequent ionization process and induces fast oscillation with constant period in the laser intensity dependence of the asymmetry parameter. The dominant contribution to the fast oscillation comes from the mixed interference between different pairs of returning orbits in different excitation channels. However, the oscillation disappears after laser focus averaging is performed due to its rather small period.