Figure 4
Map of return energies, as a function of ellipticity ε and ionization time ti.
Ip is the ionization potential of the ground state. Plotted are also isoenergetic curves corresponding to the harmonics of the fundamental field, and the cut-off energy (shown by the solid black line), which decreases for increasing ellipticity. Trajectories, which are ionized earlier than the cut-off energy, correspond to the long trajectories. It is easy to see that a specific time of ionization does not correspond to a certain recombination energy.
