XUV+IR ionization of Ar

A. A. GRAMAJO; D. G. ARBÓ; R. DELLA PICCA; S. D. LÓPEZ

Budapest

Conferencia; The International Conference on Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces; 2018

EKHO' 94 Ltd., Debrecen

The laser-assisted XUV photoelectric effect (LAPE) occurs when extreme ultraviolet (XUV) and infrared (IR) lasers overlap in space and time. In this case, the photoelectron spectrum is factored into two contributions: one that accounts for the intracycle (during one IR cycle time interval) electron emission and the second one describing the intercycle interference (due to the emission at different IR cycles) [1,2,3]. This intercycle interference is the responsible of the well-know ?sidebands? (Sbs) in the photoelectron spectrum separated at energy values given byEn = nωL + ωX - Ip - Up (1) where ωX(L) is the frecuency of XUV(IR) pulse, Ip is the ionization energy, Up the ponderomotive energy and n is the number of absorbed or emitted IR photons.In the present work we consider the Argon photoionization from the subshells 3s, 3p0 and 3p1 due to a short XUV pulse assisted by an IR laser both linearly polarized. Within the continuum-distorted wave Strong Field Approximation (SFA) supported by the ab initio solution of the time-dependent Schrödinger equation (TDSE) we study the angle-resolved momentum distribution of photoelectron for the case that both fields are linearly polarized. We analyze and characterize the modulation of both factors, the intra- and intercycle contributions, on the spectrum.In particular, we study several geometrical arrangements between the polarization vectors and the emission direction, that give rise to selective photoelectron sideband energies in the the ionization spectrum, as in the case of perpendicular emission where only odd sidebands are observed (see figure (b) and [3]).