Analysis of the impact of circularly polarized negatively chirped laser pulse width on electron radiation

To improve the characteristics of nonlinear Thomson scattering radiation, a numerical study is conducted on the motion characteristics and radiation properties of stationary electrons driven by circularly polarized negatively chirped laser pulses with different pulse widths. The results indicate that as the pulse width increases, electron radiation collimation decreases, while the azimuth angle is insensitive to pulse width changes. In the time spectrum, the peak radiation power reaches the order of 10⁸ to 10⁹, showing new characteristics with pulse width variation. The peak radiation power exhibits an extremum rather than increasing with decreasing pulse width, providing a practical method for modulating ultra-short pulse radiation sources. In terms of the observation direction of peak radiation power, the radiation spectrum broadens with increasing pulse width, and radiation monochromaticity decreases, indicating that there is an optimal pulse width for negatively chirped laser pulses that allows strong peak radiation power with minimal monochromaticity attenuation.