Calculation and Optimization of Laser Acceleration in Vacuum

Extraordinarily high fields generated by focused lasers are envisioned to accelerate particles to high energies. In this paper, we develop a new method to calculate laser acceleration in vacuum based on the energy exchange arose from the interference of the laser field with the radiation field of the particle. We apply this method to a simple accelerating structure, a perfectly conducting screen with a round hole, and show that how to optimize the energy gain with respect to the hole radius, laser angle and spot size, as well as the transverse profile of the laser. Limitation and energy scaling of this acceleration method are also discussed