Direct Laser-Driven Electron Acceleration and Energy Gain in Helical Beams

Etele Molnár,Dan Stutman

doi:10.1155/2021/6645668

Abstract

A detailed study of direct laser-driven electron acceleration in paraxial Laguerre–Gaussian modes corresponding to helical beams LG0m with azimuthal modes m = {1,2,3,4,5} is presented. Due to the difference between the ponderomotive force of the fundamental Gaussian beam LG00 and helical beams LG0m, we found that the optimal beam waist leading to the most energetic electrons at full width at half maximum is more than twice smaller for the latter and corresponds to a few wavelengths Δw0 = {6,11,19}λ0 for laser powers of P0 = {0.1, 1,10} PW. We also found that, for azimuthal modes m ≥ 3, the optimal waist should be smaller than Δw0 < 19λ0. Using these optimal values, we have observed that the average kinetic energy gain of electrons is about an order of magnitude larger in helical beams compared to the fundamental Gaussian beam. This average energy gain increases with the azimuthal index m leading to collimated electrons of a few 100 MeV energy in the direction of the laser propagation.

Highlights

Ese distinctive properties of higher-order Laguerre–Gaussian modes set forth to an ever-increasing amount of applications in different areas of optical communications, imaging techniques, quantum information technologies, and other topics; see [2,3,4,5,6] and references therein
We are interested in the values of the beam waist for different laser powers that lead to maximal energy gains, in case of the Gaussian beam LG00 and the helical beams LG01, LG02, LG03, LG04, and LG05
We have studied and compared the direct laserdriven electron acceleration in Laguerre–Gaussian beams with azimuthal mode indices, LG00 corresponding to the fundamental Gaussian beam, and helical beams LG01, LG02, LG03, LG04, and LG05

Summary

Etele Molnar and Dan Stutman

Vacuum-based charge acceleration with Laguerre–Gaussian beams has been studied very recently [18, 19] showing that it is possible to generate GeV high-quality electron bunch with low spread in energy and radial deflection. Motivated by these interesting results, in this paper, we will study direct electron acceleration in vacuum in various helical Laguerre–Gaussian LG0m laser pulses corresponding to helical modes m {0, 1, 2, 3, 4, 5}.

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