A Lorentz and gauge invariant measure of laser intensity
arXiv:0807.1841 · doi:10.1016/j.optcom.2009.01.051
Abstract
Focussing on null fields as simple models of laser beams we discuss the classical relativistic motion of charges in strong electromagnetic fields. We suggest a universal, Lorentz and gauge invariant measure of laser intensity and explicitly calculate and interpret it for crossed field, plane wave and vortex models.
4 pages, 2 .eps figures