Controlling electron collision by counterrotating circular two-color laser fields*

Abstract

Electron collision as well as its controlling lies in the core of study on nonsequential double ionization (NSDI). A single collision occurred in a convergent time is important to disclose the essential features of the electron correlation. However, it is difficult to form such a collision. By using counterrotating circular two-color (CRTC) laser fields, we show that a single electron collision can be achieved in a convergent time and a net electron correlation is set up within the sub-femtosecond time scale in the NSDI process of Ar atoms. The proposed method is also valid for other atoms, provided that one chooses the frequency and intensity of the CRTC field according to a scaling law.

Effects of initial electronic state on vortex patterns in counter-rotating circularly polarized attosecond pulses*

“…[5] The ultrashort attosecond pulses can also induce electron charge migration, thus offering the possibility for probing the molecular structure and imaging the molecular reactions. [6][7][8] In the research, a variety of pulses and their combinations have been used to explore electron dynamics, including the high-order harmonic generation (HHG), [9][10][11][12][13][14] nonsequential double ionization (NSDI), [15][16][17][18] and the photoelectron momentum distribution (PMD). [19][20][21][22][23] Recently it was found that single ionization of atom by two oppositely circularly polarized, time-delayed attosecond pulses produce vortex patterns in PMDs, [24][25][26][27] which are sensitive to the time delay between the pulses, their handedness, and their relative phase.…”