Laser-induced Autoionization in the Presence of Several Atomic Continua

Abstract

Much attention is being paid lately to the theoretical investigation of laser–induced autoionization[1–12]. The strong laser coupling of the initial (e.g., ground) state of the atom to the auto-ionizing state (AS) introduces new, nonlinear phenomena, such as the “population trapping”[5,6] or the dramatic narrowing of the photoelectron spectra[2] near the point of “confluence of coherences”, i.e. when one of the peaks of the Autler-Townes doublet coincides with the Fano[13] zero. The early works[1,2] in the field concerned very simplified models of the process. Subsequent studies have shown that the influence of relaxation mechanisms, such as spontaneous emission[3,4], inhomogeneous (e.g. Doppler) broadening[7] or transverse relaxation[8,9] (e.g. laser incoherences in the phase diffusion model) leads to the broadening of the sharp peak in the photoelectron spectra.