Symmetry of nonlinear inverse Thomson scattering with initial phase modulation of ultrashort circularly polarized laser

Abstract

Nonlinear inverse Thomson scattering (NITS) has gained many applications as premium x-ray sources, and is of great research values. Based on the classical theory of NITS, the effects of laser’s initial phase on NITS radiation are analyzed through numerical simulation when the relativistic electron collides with a circularly polarized ultrashort intense laser pulse. When pulse width of the laser is very short, the initial phase has a significant impact on the symmetry of electron’ trajectory and spatial radiation power, and the electrons’ trajectories show a ‘triple symmetry’ property with respect to the initial phase. The angular distribution of NITS radiation energy is generally circular, but there is a prominent single peak, which shows the high collimation. The direction and energy of the radiation peak can be modulated by initial phase periodically. Furthermore, the symmetry of radiate spatial spectrum varies with the change of initial phase, but the distribution pattern of the spectrum remains unchanged. Broad-band x-rays with different wavelength widths can be obtained at different positions in space. The findings above show that it is feasible to use initial phase of the laser to modulate the symmetry of the x-rays generated by NITS, which also provides a numerical basis for obtaining x-rays with different wavelength widths in practical experiments.