Electron acceleration by relativistic surface plasmons in laser-grating interaction

TL;DR

This paper demonstrates that relativistic surface plasmons excited by ultra-intense lasers on grating targets can efficiently accelerate electrons to energies above 10 MeV, with potential applications in compact electron sources and high field plasmonics.

Contribution

It provides experimental evidence and simulation support for relativistic surface plasmon-driven electron acceleration in laser-grating interactions, a novel mechanism for high-energy electron generation.

Findings

Enhanced electron emission at resonant angles

Electron energies exceeding 10 MeV observed

Simulations confirm relativistic surface plasmon role

Abstract

The generation of energetic electron bunches by the interaction of a short, ultra-intense ($I>10^{19} \textrm{W/cm}^2$) laser pulse with "grating" targets has been investigated in a regime of ultra-high pulse-to-prepulse contrast ($10^{12}$). For incidence angles close to the resonant condition for Surface Plasmon (SP) excitation, a strong electron emission was observed within a narrow cone along the target surface, with energies exceeding 10 MeV. Both the energy and the number of emitted electrons were strongly enhanced with respect to simple flat targets. The experimental data are closely reproduced by three-dimensional particle-in-cell simulations, which provide evidence for the generation of relativistic SPs and for their role in driving the acceleration process. Besides the possible applications of the scheme as a compact, ultra-short source of MeV electrons, these results are a step forward the development of high field plasmonics.