Initial phase-sensitivity of spatial characteristics in the tightly and non-tightly focused linearly polarized few-cycle region

摘要

Within the frame of electrodynamic and nonlinearly Thomson scattering, we study the initial phase-sensitivity with respect to spatial characteristics of a static electron irradiated by Guassian linearly polarized few-cycle laser pulse for different beam waists. With the combination and comparison of the electron's real-time motion and radiation conditions, the initial phase-sensitivity turns out with inverse proportional relation to the beam waist where the radiation's transverse shift of varied initial phases is irregular in the non-tightly focused case. Furthermore, by changing the initial phases, the petal-like full spatial radiation pattern changes from 4 unstable pieces to 2 constant pieces and the radiated energy shift slows down with the beam waist evolving from b_0 = 1 to b_0 = 10. Finally, with initial phase Φ_0 increasing from 0 to π we discover an interesting phenomenon for the first time, where the normalized maximal radiated power and corresponding azimuth angle fluctuate in the form of ripples and ladders in tightly-focused case b_0 = 1, in contrast to the perfectly symmetry with respect to Φ_0 = 0.57π for the maximal radiated power in non-tightly focused case b_0 = 10.