Accurate description of ultra-short tightly focused Gaussian laser pulses and vacuum laser acceleration

摘要

High-order correction terms to the expression of the field of ultra-short tightly focused Gaussian laser pulses are derived. Terms up to seventh order in the small dimen-sionless spatial parameter s = 1/(k_0w_(00)) and first order in the small dimensionless temporal parameter ε = 1/(ω_0t_0) are explicitly presented (ω_0 = ck_0 the central oscillatory frequency, 2t_0 the pulse duration, w_(00) the beam waist radius at the central frequency ω_0). To evaluate the correction efficacy, both the corrected and the paraxial field equations are used in detailed simulation studies of laser/electron interaction dynamics. Special attention is given to the vacuum laser acceleration scheme. The influence on the electron dynamics due to the diffraction edge field of a tightly focused laser beam is also investigated.