Radiation spectrum characteristics of circularly polarized laser colliding electrons at different intensities

Within the framework of nonlinear Thomson scattering, the spectral properties of the electromagnetic radiation emitted by a tightly focused circularly polarized laser pulse acting on relatively moving electrons at different intensities are studied in detail, starting from a single-electron collision model. Through theoretical analysis and computer simulations, we investigate that the spectrum on θ = 180°has good quasi-monochromaticity for a0>1. While in the 0 case of a0>1, multiple discrete bandwidths appear in the θ = 170° as well as θ = 190° directions, and the quasi- 0 monochromaticity of the radiation spectrum is always better than that of θ = 180° with asymmetry. In addition, it is found that the laser intensity is positively correlated with the bandwidth of the radiation spectrum on θ = 180° and negatively correlated with the peak of the spectrum at the same angle. And as the laser intensity increases, the radiation energy expands in the direction of decreasing angle θ , and the radiation spectrum gradually broadens to high frequency at the maximum peak power angle θm .