Relative phase effect of nonsequential double ionization in Ar by two-color elliptically polarized laser field*

Abstract

We investigated the nonsequential double ionization (NSDI) in Ar by two-color elliptically polarized laser field with a three-dimensional (3D) classical ensemble method. We study the relative phase effect of NSDI and distinguish two particular recollision channels in NSDI, which are recollision–impact ionization (RII) and recollision-induced excitation with subsequent ionization (RESI), according to the delay-time between the recollision and the final double ionization. The numerical results indicate that the ion momentum distribution is changed and the triangle structure is more obvious with the decrease of the relative phase. We also demonstrate that the RESI process always dominates in the whole double ionization process and the ratio of RESI and RII channels can be influenced by the relative phase.

Influence of relative phase on the nonsequential double ionization process of CO2 molecules by counter-rotating two-color circularly polarized laser fields

“…So the relative phase is in the range of ( ) / p 0, 2 , the NSDI yield reach its maximum at / f p = 3 16, its minimum at / f p = 7 16. The main reason for this phenomenon is that the yield of NSDI is affected by the angle between the electric field and the molecular axis [24]. As the relative phase increases the three-lobed structure of electric field begins to rotate, which will cause the angle between each lobe of the electric field and the molecular axis increase and decrease periodically.…”

“…In the study of two-electron emission dynamics process of NSDI, the interference of the relative phase on the angular distributions and RC is a hot topic. As the relative phase decreases, the triangular structure of the negative vector potential changes significantly, resulting in a change in the ion momentum distribution [23,24]. Emission direction of the electrons changes with the relative phase, which is causes of RC time and the return angle of the first electron is determined by relative phase of the CRTC laser fields [25].…”

“…However, for atoms, because of their spherically symmetry, the relative phase change will not affect the yield. In the above studies [23][24][25], the dependence of NSDI yield on the relative phase for simple diatomic molecules in CRTC laser fields has been discussed. But the influence of the relative phase on NSDI yield for linear triatomic molecules by CRTC laser fields has not been specifically concerned.…”

The Coulomb effect in nonsequential double ionization by counter-rotating two-color elliptical polarization fields

“…The TCEP field has been employed to induce highorder harmonic generation, 46,47 above-threshold ionization, 48 molecule dissociation 49 and NSDI. 50,51 It is shown that the electron momentum distributions are asymmetric in TCEP fields and the electron returning direction depends on the relative phase of two elliptical fields. Here, we fix the major axis of 1600 nm elliptical field in the x direction and rotate the major axis of 800 nm elliptical field to study the effect of the relative alignment of two elliptical fields on ultrafast dynamics in NSDI by TCEP fields.…”

Strong-field response time and its implications on attosecond measurement

“…Attosecond optics is closely associated with strong-field physics. The interaction of intense laser fields with atoms and molecules [1,2] produces abundant ultrafast physical phenomena, such as above-threshold ionization (ATI), [3][4][5][6][7][8] high-order harmonic generation (HHG), [9][10][11][12][13][14] and non-sequential double ionization (NSDI), [15][16][17][18][19] etc. These phenomena have been further applied to ultrafast measurements of electron dynamics in atoms and molecules, [20,21] with achieving unprecedented time resolution of attosecond.…”