Recollision of excited electron in below-threshold nonsequential double ionization

Abstract

Recollision is the most important post-tunneling process in strong-field physics, but so far has been restricted to interaction between the first ionized electron and the residual ion in nonsequential double ionization. Here we identify the role of recollision of the second ionized electron in the below-threshold nonsequential double ionization process by introducing a Coulomb-corrected quantum-trajectories method. We will reproduce the experimentally observed cross-shaped and anti-correlated patterns in correlated two-electron momentum distributions, and the transition between them. Both the cross-shaped and anti-correlated patterns are attributed to recolliding trajectories of the second electron. The effect of recollision of the second electron is significantly enhanced by the stronger Coulomb potential of the higher valence residual ion, and is further strengthened by the recapture process of the second electron. Our work paves a potential way to image ultrafast dynamics of atoms and molecules in intense laser field.

Entanglement of orbital angular momentum in non-sequential double ionization

“…Full inclusion of the Coulomb potential is also an important consideration. Recent work demonstrated the inclusion of the Coulomb potential introduced recolliding trajectories for the second electron 78 . However, this treatment uses the same S-matrix treatment for the recollision-excitation step, allowing for entanglement via the same mechanism.…”

“…By measuring the OAM, we are able to (i) disentangle the channels of excitation with differing quantum magnetic numbers, not possible in an uncorrelated system, and (ii) access coherence terms, yielding phase information not accessible in a classically correlated system. Results, which include the Coulomb potential in the electron propagation for RESI 78 , show that recollision of the second electron plays an important role. Thus, trajectories will interfere with differing amounts of interaction with the Coulomb potential, providing holographic interferences 15 .…”

The modeling non-sequential double ionization of helium atom under high-intensity femtosecond laser pulses with shielding charge approximation

“…Double ionization has been observed in experimental studies [16][17][18][19] and modeled with the theory. Various models are employed to explain non-sequential double ionization, including the classical ensemble [20][21][22][23][24][25], S-matrix [26,27], quantitative re-scattering (QRS) model [28,29], and the solution of the time-dependent Schrödinger equation (TDSE). Out of these models, the numerical solution of TDSE is widely regarded as being more accurate [30][31][32].…”

High-order harmonic generation, attosecond pulse, and non-sequential double ionization in the helium atom under high-intensity femtosecond laser pulses

“…Truong et al [30] believed that TDSE, despite its computational demands, cannot accurately track the physical propagation of ionized electrons. Therefore, they utilized a classical ensemble model with an Ar atom and a Coulomb potential (a 1.5 = ) to obtain a knee structure within an intensity range of / I 4.0 10 W cm = The knee structure has been investigated in numerical simulations using various techniques, including classical ensembles [30][31][32], S-matrix [33,34], and the numerical solutions of the one-dimensional timedependent Schrödinger equation (TDSE) [35,36]. A more detailed discussion on this topic can be found in [37].…”