Investigation of interference effect during ionization of hydrogen atom in bichromatic laser fields of circular polarization

We theoretically investigate the strong-field ionization of hydrogen atom in bichromatic laser fields of circular polarization by calculating the momentum distributions. We find that the momentum distributions consist of a series of arc fringes, which correspond to the different above-threshold ionization peaks, and the momentum distributions generally are inversion asymmetric owing to the interference happening between the different ionization channels. But if only one ionization channel is considered, the momentum distributions are perfect and concentric rings, and as the number of ionization channel increases, the asymmetry of the momentum distribution becomes more and more notable. (C) 2013 Elsevier B.V. All rights reserved.