Effect of temporal asymmetry of the laser pulse on electron acceleration in vacuum

Abstract

Abstract We explore the electron dynamics in a Gaussian laser pulse to assess the contribution of the temporal parameters to the mechanism of vacuum laser acceleration. Our numerical study reveals that a considerable nonzero energy gain can be achieved through a spatio-temporally controlled electron injection. Moreover, three-dimensional optimization of the electron’s injection angle suggests that the highest energy gain is obtained by using a sideways injection scheme. We also present the dependence of the electron energy gain on the laser polarization by comprehensively comparing all possible polarization states. It is found that the temporal sensitivity of the electron injection is determined by the polarization of the laser pulse. In addition, it is shown that although the energy gain is maximized in linearly polarized short laser pulses, circularly polarized laser pulses with longer duration would also lead to comparable energy gains but with much less temporal sensitivity for electron injection. To address the technical feasibility of the acceleration procedure under the mentioned optimized conditions, an experimental setup is proposed.