Comparative Analysis of Electron Acceleration by Laser Pulse in Flat and Chip Dielectric Structures

A comparative analysis of two types of dielectric laser accelerators (DLA) based on periodic (grating) and flat dielectric structures to accelerate electrons in the energy range from 300 keV to 3 GeV is presented. The main attention is paid to the conditions, efficiency and restrictions of each acceleration method, as well as the influence of laser radiation parameters on electron acceleration processes. Single and double (both grating and flat) dielectric structures and their impact on acceleration are considered. For the study of two types of quartz DLA, the Ti:Sa laser system with a generation band width 790-810 nm (FWHM), the laser electric field 6 GeV/m are used. The study showed that a flat dielectric structure provides more effective acceleration in a wide range of energies, especially with a symmetrical geometry (double structures), compared with the periodic structure. If we consider only a periodic structure, then with the selected symmetrical geometry, for the ultra relativistic electrons, it demonstrates the acceleration rate two times of magnitude more than for single configuration. However, the use of a one-sided periodic structure turns out to be preferable for accelerating electrons with moderate energies, ~0.5-0.9 MeV, where the acceleration rate in a one-sided configuration is higher than in a symmetric (double) periodic structure. The space-time distributions of laser-excited electromagnetic fields in the accelerating channel and their influence on the electron beam is analyzed also. The advantage of a flat structure over a periodic one, which arises due to the design features of the corresponding dielectric accelerators, is discussed.