Laser induced electron acceleration in vacuum

Electron acceleration by a plane polarized laser wave has been studied in vacuum. Relativistic equations of motion have been solved exactly for electron trajectory and energy as a function of laser intensity, phase θ of the laser wave and initial electron energy. The electric field of the laser wave is taken as E=xA0 cos(ωt-kz+θ). Electron energy is maximum when θ=π/2 and (ωt-kz)=(2n-1)π, where n=1,2,3,... . The peak electron energy increases with laser intensity and initial electron energy. If a propagating laser pulse is abruptly stopped by a thin foil, the highly energetic electrons will continue to move forward inertially and escape from the pulse, as well as the thin foil, without much loss in the energy, if their stopping distance is much larger than the laser skin depth and the thin foil thickness, respectively