The relativistic motion and radiation spectrum of free electrons in the focus of an ultrashort high intensity laser pulse is solved. Motion and radiation of electrons in a novel axicon focus is also analyzed. We have calculated the radiation emitted from free electrons in an ultrashort pulsed laser focus. For low electron densities, where space charge is negligible, we find that ponderomotive forces limit the effective volume where the radiation is emitted to a region much smaller than the fundamental wavelength. Nonetheless, constructive interference plays a significant role in the collective radiation spectrum.
This article is from 'Osa Proceedings of the Topical Meeting (5th) on Short-Wave Length Coherent Radiation: Generation and Applications Held in Monterey, California on 8-10 April 1991. Volume 11,' AD-A252 973, p252-256.