Two-photon double ionization of helium by chirped few-cycle attosecond pulses: From nonsequential to sequential regime
Tong Yao1, Jiang Wei-Chao1, 2, Wu Pan1, Peng Liang-You1, 3, †,
       

Singly differential ionization probabilities dP/dE, calculated by integrating one of the two variables in P(E1,E2), for different central photon energy ω0: (a) 45 eV, (b) 52.4 eV, and (c) 70 eV. In each panel, the results are shown for three different chirp parameters ξ, i.e., 0 (solid), 1.75 (dash-dotted), and −1.75 (dashed).