Dynamic resonances in ultra-short laser pulses

Dynamic multiphoton resonances in ultra‐short superintense laser pulses consisting of 50–200 field periods are considered numerically for a two‐level system. The impact of nonresonant (Bloch‐Siegert) and carrier‐envelope effects on the dynamics of a two‐level system was studied numerically, and conditions for complete population inversion were derived. The widths of multiphoton resonances increase with the increasing of the laser field. Results do not depend practically on the pulse duration. Effective resonance frequencies for multiphoton resonances increases strongly in a super‐intense field. Multiphoton resonances are shifted and unified with each other in super‐intense laser fields. (© 2007 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)