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, †,}

Contour plots of the angle-integrated joint energy distribution of both ejected electrons P(E₁,E₂) for ω₀ = 70 eV, at three different chirp parameters: (a), (d) ξ = − 1.75, (b), (e) ξ = 0, and (c), (f) ξ = 1.75, respectively, calculated by TDSE (first row) and by TDPT (second row).