Three-dimensional dielectric photonic crystal structures for laser-driven acceleration

Benjamin M Cowan

doi:10.1103/physrevstab.11.011301

Abstract

We present the design and simulation of a three-dimensional photonic crystal waveguide for linear laser-driven acceleration in vacuum. The structure confines a synchronous speed-of-light accelerating mode in both transverse dimensions. We report the properties of this mode, including sustainable gradient and optical-to-beam efficiency. We present a novel method for confining a particle beam using optical fields as focusing elements. This technique, combined with careful structure design, is shown to have a large dynamic aperture and minimal emittance growth, even over millions of optical wavelengths.

Highlights

The extraordinary electric fields available from laser systems make laser-driven charged particle acceleration an exciting possibility
We find that the woodpile structure couples much more strongly to a particle beam than an rf accelerator, with a loss factor of 5:56 109 V=m=pC versus 19:7 V=m=pC for the SLAC linac [17]
We have found numerically an accelerating mode in a three-dimensional dielectric photonic crystal structure

Summary

INTRODUCTION

The extraordinary electric fields available from laser systems make laser-driven charged particle acceleration an exciting possibility. Manufacturing a circular disk-loaded waveguide on such small scales poses a significant challenge. For these reasons, we must consider structures which differ significantly from those used in conventional accelerators. The experiment demonstrated the expected linear scaling of energy modulation with laser electric field as well as the expected polarization dependence. Photonic crystals [4] provide a means of guiding a speed-of-light optical mode in an all-dielectric structure. They have been investigated for some time for metallic rf accelerator structures because of their potential for eliminating a major source of beam breakup instability [5,6].

STRUCTURE GEOMETRY AND ACCELERATING MODE

PERFORMANCE OF THE ACCELERATING MODE

PARTICLE BEAM DYNAMICS

Findings

CONCLUSION