Polarization-dependent control of ionization pathways in atomic strong-field nonsequential double ionization.

Utilizing a classical ensemble model (CEM), we have studied the rescattering behavior of quasi-free tunneling electron and correlation dynamics of electron pair during nonsequential double ionization (NSDI) of Xe atoms induced by a counter-rotating, two-color, elliptically polarized (TCEP) laser field. Our numerical results reveal that the momentum of the first tunneling electron is predominantly located in the third quadrant of momentum spectrum, whereas the momentum spectrum of the second electron presents a triangular structure along the direction of the negative vector potential of driving field. This phenomenon occurs because the first electron has greater emission kinetic energy than the second one, rendering the latter more sensitive to the influence exerted by the electric field vector potential.

Modulation of electron correlation dynamics in atomic non-sequential double ionization by counter-rotating two-color circularly polarized laser fields.

We investigate the ultrafast electron correlation effects during non-sequential double ionization (NSDI) of argon subjected to a combined femtosecond field composed of counter-rotating two-color circularly polarized (TCCP) pulse laser using a 3D classical ensemble model (CEM). Our simulation results reveal that manipulation of the carrier-envelope phase (CEP) of the external driving field modulates the dynamical behavior of the two electrons, resulting in a notable sensitivity of their momentum distribution to the relative phase of two components of the counter-rotating TCCP field. Through inversion analysis, we uncover the capability to direct electrons toward a single direction, thereby facilitating focused ion-electron collisions on the attosecond timescale.

Exploring tunneling time by instantaneous ionization rate in strong-field ionization.

A quantum approach is presented to investigate tunneling time by supervising the instantaneous ionization rate. We find that the ionization rate peak appearance lags behind the maximum of electric field intensity for a linearly polarized pulse. This time delay interval can be taken to characterize the tunneling time.