X-ray absorption in atoms in the presence of an intense laser field

Abstract

We consider the deep-level absorption of x rays in atoms in the presence of an intense laser field. The laser field is considered to be small relative to atomic fields but strongly interacting with the outgoing electron, represented here by a plane wave. The general expression for the x-ray absorption cross section as a function of the laser field is obtained using the two methods of power-series expansion and asymptotically large fields. We find that for low fields, the cross section increases as the square of the field, while for large fields it decreases asymptotically as the inverse power of the field.