Spatial and spectral characteristics of nonlinear Thomson scattering in the few-cycle regime

Abstract

Based on classical radiation theory, the electron relativistic dynamics, full spatial and spectral characteristics of nonlinear Thomson scattering in a linearly polarized intense few-cycle laser pulse have been investigated theoretically and numerically. In the few-cycle laser pulse, the electron relativistic dynamics depends sensitively on the initial phase of the driving laser pulse. The Thomson scattering radiation also shows many remarkable initial phase-sensitive characteristics. For most of the initial phases, the x–y plane and y–z plane symmetry of radiation angular distributions is broken down, i.e., the well-known fourfold symmetry disappears. The radiation spectra also depend on the initial phase and show a y–z plane asymmetry for most initial phases. These phenomena can be attributed to the properties of the few-cycle pulse. Moreover, possible ways to observe these phenomena are suggested. In addition, we propose that the initial phase-sensitive characteristics of nonlinear Thomson scattering can be utilized to determine the initial phase of the intense few-cycle pulse.