Abstract

The utilization of X-rays produced by interaction between relativistic electrons and laser pulses finds profound application in domains such as photoelectron spectroscopy. Through numerical simulation, the influence of the laser pulse delay time τ0 and the initial Lorentz factor γ0 on the spatial and spectral properties of radiation produced by electron cross collision with a circularly polarized laser pulse is investigated. Also, the optimal parameters for generating quasi-monochromatic pulses and high-order harmonic radiation are discussed. The results reveal that when |τ0| is large, the electron collides with the leading or trailing edge of the laser pulse, resulting in superior quasi-monochromatic radiation pulses. However, when τ0=0, the electron collides with the center of the laser pulse, which is most favorable for the generation of high-order harmonics. Furthermore, γ0 has a negligible impact on the monochromaticity of the fundamental harmonic but plays a detrimental role in forming a single quasi-monochromatic pulse at higher values. Instead, higher γ0 promotes the broadening of high-order harmonics. These results are important for obtaining radiating X-rays with different properties according to practical requirements.