Intensity dependence of plateau structures in laser-assisted x-ray–atom scattering processes

Authors

• Dejan B. Miloševic, University of Nebraska - Lincoln
• Anthony F. Starace, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

November 1999

Comments

Published by American Physical Society. Phys. Rev. A A 60, 3943 (1999). http://pra.aps.org. Copyright © 1999 American Physical Society. Permission to use.

Abstract

The dependence on laser intensity of recently discovered plateau structures in laser-assisted x-ray–atom scattering, both with and without a static electric field present, is analyzed. Using the “three-step” model and the strong-field approximation we demonstrate a connection between laser-assisted, x-ray–atom scattering and high-order harmonic generation: For high laser-field intensities without a static field present, both processes have plateaus whose energies extend to the cutoff value 3.17U_p, where U_p is the ponderomotive potential energy. For x-ray–atom scattering in the presence of a static electric field we show that at high laser-field intensities two plateaus appear: One is our recently predicted high-energy plateau for the same process [Phys. Rev. Lett. 81, 5097 (1998)], while the other, low-energy plateau, has a differential cross section six orders of magnitude larger. The energy positions and relative magnitudes of these new plateaus are explained using semiclassical arguments.