Periodic structure of different dielectric layers for dielectric laser accelerators.

In this paper, a periodic structure of different dielectric layers is proposed and investigated for relativistic electron acceleration. The periodic dielectric structure provides an accelerating electric field inside the structure. Results show that the electron beam can experience a strong electric force in one direction during propagation in the structure, leading to the acceleration gradient increasing by more than double in comparison with dual-grating structures. Acceleration gradient enhancement occurs without increasing the electric field much inside the structure; therefore, the maximum achievable acceleration gradient and acceleration factor are increased by more than 100%, reaching 0.7. Thereby, by using the proposed structure GV/m, the acceleration gradient can be achieved with a wide electron channel. Also, the required input laser fluence is reduced for the same acceleration gradient. Acceleration gradient and acceleration factor optimization is done corresponding to structure parameters. Our work shows that the proposed structure helps to make dielectric laser accelerators more efficient.