Two-color XUV plus near-IR multiphoton near-threshold ionization of the helium ion by circularly polarized light in the vicinity of the 3p resonance

Two-color XUV plus near-IR multiphoton ionization of the helium ion by circularly polarized light is studied in the vicinity of the 3p resonance. Combining the analysis of results obtained by solving the time-dependent Schrodinger equation and that of the quasienergy spectrum of He+ reveals the physical mechanisms that determine the photoelectron spectra and the variation of the circular dichroism as a function of the near-IR intensity.