Published in Laser Physics, Volume 11, Issue 9, January 1, 2001, pages 982-988. This is a preprint of an article published in Laser Physics - Copyright © 2001 Astro, Ltd. or copyright owner as specified in the Journal - Published by International Academic Publishing Company "Nauka/Interperiodica".Springer.
NOTE: At the time of publication, the author Glen Gillen was not yet affiliated with Cal Poly.
The study of above-threshold ionization (ATI) is now over 20 years old and much has been learned about the interaction of a single atomic electron with intense laser fields. The development of stable, high repetition rate ultrashort pulse laser systems has allowed experiments to probe intricate details of the ionization process using photoelectron and photoion spectroscopies. To date the overwhelming majority of data show that intense laser fields interact with only a single electron at a time to produce the well known features in electron kinetic energy spectra. We will present an overview of state-of-the-art experiments in ATI and show what can be learned about multielectron effects using careful measurements. Argon data showing the dominance of single electron physics at laser intensities near and below 1014 W/cm2 will be shown. In addition, new data taken with a model two-electron system (magnesium) continues the search for detailed a understanding of intense field interactions in complex atoms. In all cases the current status of what we learn using ATI will be shown and discussed.