Analytic confirmation that the factorized formula for harmonic generation involves the exact photorecombination cross section

Authors

• M. V. Frolov, Voronezh State University, RussiaFollow
• N. L. Manakov, Voronezh State University, RussiaFollow
• T. S. Sarantseva, Voronezh State University, RussiaFollow
• Anthony F. Starace, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

4-2011

Comments

Published in PHYSICAL REVIEW A 83, 043416 (2011). Copyright © 2011 American Physical Society. Used by permission.

Abstract

High-order-harmonic generation (HHG) by atoms in a strong laser field is analyzed theoretically, taking into account atomic potential effects beyond the strong field approximation (SFA). Our analytical derivation extends the time-dependent effective range (TDER) theory, developed previously for a short-range potential supporting only a single bound state, to the case of a potential supporting two bound states having different angular momenta and dynamically interacting with the continuum. In contrast to the SFA and the single-state TDER model, in both of which the HHG rates in the region of the high-energy plateau cutoff involve only the plane-wave (first Born) approximation for the photorecombination cross section, our analytic expression for the HHG rates in the two-state TDER model involves the exact photorecombination cross section for this model. These results justify the factorization of HHG rates in the high-energy plateau region in terms of the electron wave packet and the exact (non-Born) photorecombination cross section, which was suggested previously using only phenomenological arguments.