Two-photon double ionization of helium by chirped few-cycle attosecond pulses: From nonsequential to sequential regime

Tong Yao¹, Jiang Wei-Chao^{1, 2}, Wu Pan¹, Peng Liang-You^{1, 3, †,}

Total two-photon double-ionization probability P_total as a function of the chirp parameter ξ, respectively, calculated by TDSE (squares) and by TDPT (triangles), for four different central photon energies ω₀: (a) 45 eV, (b) 52.4 eV, (c) 60 eV, and (d) 70 eV.