Generating elliptically polarized isolated attosecond pulses from the 2p0 state of He+ with a linearly polarized two-color field

We theoretically investigate the generation of elliptically polarized isolated attosecond pulses from He+ prepared in an initial 2p0 state with a linearly polarized two-color field. It is shown that the elliptically polarized broadband supercontinuum can be produced via controlling the acceleration step of high-order harmonic generation using a two-color field. Then elliptically polarized isolated attosecond pulses can be obtained by filtering the supercontinuum. In addition, we find that the ellipticity of attosecond pulses corresponding to the short trajectory is larger than that corresponding to the long trajectory for all the polarization directions of the driving field. Further analysis reveals that the influence of the Coulomb effect to the dynamics of the continuum electrons is responsible for the difference.