Dielectric laser acceleration of nonrelativistic electrons at a single fused silica grating structure: Experimental part

John Breuer,Roswitha Graf,Alexander Apolonski,Peter Hommelhoff

doi:10.1103/physrevstab.17.021301

Abstract

Recently, our group has demonstrated dielectric laser acceleration of nonrelativistic electrons at a scalable fused silica grating [J. Breuer and P. Hommelhoff, Phys. Rev. Lett. 111, 134803 (2013)]. This represents a demonstration of the inverse Smith-Purcell effect in the optical regime. The third spatial harmonic of the grating, which is excited by Titanium:sapphire laser pulses, synchronously accelerates 28 keV electrons derived from an electron microscope column. We observe a maximum acceleration gradient of $25 \text{MeV}/\text{m}$. Here we present the experimental setup in detail. We describe grating-related issues such as surface charging and alignment as well as damage threshold measurements. A detailed explanation of the detection scheme is given. Furthermore, extensive numerical simulations are discussed, which agree well with the experimental results.

Highlights

Laser-driven particle acceleration has been proposed just two years after the realization of the first lasers because it was clear that well-controlled and large optical field strength could be achieved [1]
Laser-driven particle acceleration bears the promise of high acceleration gradients and may lead to much smaller accelerators than achievable with conventional radio frequency linacs, which currently operate with an acceleration gradient of ∼20–50 MeV=m
We observe a maximum measured energy gain of ΔE 1⁄4 280 energy - 27.9 keV (eV). It corresponds to a maximum acceleration gradient of Gmax 1⁄4 25 MeV=m, according to Eq (6)

Summary

Introduction

Laser-driven particle acceleration has been proposed just two years after the realization of the first lasers because it was clear that well-controlled and large optical field strength could be achieved [1]. Laser-driven particle acceleration bears the promise of high acceleration gradients and may lead to much smaller accelerators than achievable with conventional radio frequency (rf) linacs, which currently operate with an acceleration gradient of ∼20–50 MeV=m. The maximum achievable acceleration gradients are limited by the damage threshold of the materials that are used to confine the accelerating fields. Because of the 1–2 orders of magnitude larger damage threshold of dielectrics at optical frequencies [4] compared to metals at microwave frequencies, as well as the rapid

Methods

Results

Conclusion