Intensity-dependent two-electron emission dynamics with orthogonally polarized two-color laser fields

Abstract

In this paper, we explore the intensity-dependent strong-field double ionization of Ne with orthogonally polarized two-color laser pulses consisting of 800-and 400-nm laser fields. The yield of Ne 2+ as a function of the relative phase φ of the two colors experiences a qualitative transition as the laser intensity decreases from the saturation regime to the far-below-saturation regime. In the saturation regime, our simulations well reproduce the recent experimental observations [Phys. Rev. Lett. 112, 193002 (2014)]. Turning to the far-below-saturation regime, however, we find that the observed small knee structure totally disappears and the maximum yield of Ne 2+ is shifted by a π/2 phase. This is explained by the competition between the trajectory concentration effect and the φ-dependent ionization rate of the tunneling electron. The possibility of controlling over the two-electron emission direction along the 400-nm field through the laser intensity is also investigated. We show that the two-electron emission direction can be reversed by changing the laser intensity for some vales of φ, while this fails for some other values of φ.

Dissociative double ionization of CO in orthogonal two-color laser fields

“…Interestingly, the OTC pulse allows us to steer the electron dynamics in both time and space domains [43,44], opening the possibility to distinguish the SDI and NSDI of molecules occurring within an intense ultrashort laser pulse. Controlled by the laser phase, the instantaneous field strength of the OTC pulse evolves as a function of both time and space, i.e., the field strength varies as it points to different directions.…”

Relative phase-dependent two-electron emission dynamics with two-color circularly polarized laser fields*

“…[41] In addition, the trajectory of every electron can be traced in the whole NSDI process with semiclassical and classical models and exhibits an intuitive picture. [24,30,42] Thus, we use the two-dimensional (2D) semiclassical ensemble model [36,37] to investigate two-electron emission dynamics of NSDI by counter-rotating TCCP laser pulses.…”

“…[28] Also, for the yield of Ne 2+ , the directions of electron-electron emission and the correlation are sensitively dependent on the relative phase in orthogonally polarized two-color (OTC) laser fields. [29,30] Recently, a number of works about NSDI in counterrotating TCCP laser fields have been reported. [7,31,32] The electron dynamics of NSDI in a laser field have been proposed and demonstrated both experimentally and theoretically.…”

Manipulating Nonsequential Double Ionization of Argon Atoms via Orthogonal Two-Color Field

“…A two-color field has more parameters that can be flexibly altered than linearly polarized laser fields, [22][23][24] such as relative polarization direction, relative initial phase, relative intensity, and relative frequency. As a result, it can be used to effectively control electron microdynamics, and it has been widely used to control a variety of strong field processes, [25][26][27][28][29][30][31][32][33][34][35][36][37] including HHG, [25,26] proton directional emission in molecular dissociation, [27] and strong field tunneling ionization, [28,29] and so on. More intriguingly, since the time and space of OTC pulses are mutually connected, the emission and re-collision of electron wave packets on the polarization plane can be established at the attosecond time scales.…”

“…[30,31] Experimental and theoretical studies show that by regulating the relative initial phase of the OTC field, the return time of the first electron wave packet can be controlled within attosecond accuracy, allowing for effective control of the electron correlation characteristics of NSDI. [32][33][34][35][36][37] In this work, we use a three-dimensional classical ensemble model to investigate the dependence of recollision dynamics and electron correlation characteristics on relative initial phase for NSDI driven by OTC fields at the relative frequency 𝛾 = 2 and 𝛾 = 3. Our results show that changing the relative initial phase of the OTC field can control the NSDI probability, and the NSDI probability trend is consistent with the returning probability.…”