Photoexcitation of atoms by cylindrically polarized Laguerre-Gaussian beams

Abstract

We analyze the photo-excitation of atoms by cylindrically polarized Laguerre-Gaussian beams within the framework of the first-order perturbation theory. To perform this analysis, we expand the vector potential of Laguerre-Gaussian beam in terms of its multipole components. For cylindrically polarized Laguerre-Gaussian beams, in particular, we show that the (magnetic) sub-components of the electric-quadrupole field vary significantly with the beam waist and radial distance in the beam cross section. We discuss the influence of multipole distribution on the transfer of total angular momentum from the Laguerre-Gaussian beam to an atom with a single electron in the valence shell. Furthermore, we explicitly show that the transition between the magnetic sub-levels of the target atom can be readily explained using the multipole distribution of the Laguerre-Gaussian beams.