All-optical three-dimensional electron pulse compression

TL;DR

This paper introduces an all-optical method for three-dimensional electron pulse compression using Hermite-Gaussian modes, enabling significant pulse shortening for ultrafast electron imaging applications.

Contribution

It presents a novel optical trapping scheme for electron pulse compression, with analytical and numerical validation demonstrating over 100-fold compression in multiple dimensions.

Findings

Achieves >100x compression in longitudinal and transverse directions.

Validates theory with Maxwell's equations for Hermite-Gaussian beams.

Applicable to various charged particles and ultrafast imaging techniques.

Abstract

We propose an all-optical, three-dimensional electron pulse compression scheme in which Hermite-Gaussian optical modes are used to fashion a three-dimensional optical trap in the electron pulse's rest frame. We show that the correct choices of optical incidence angles are necessary for optimal compression. We obtain analytical expressions for the net impulse imparted by Hermite-Gaussian free-space modes of arbitrary order. Although we focus on electrons, our theory applies to any charged particle and any particle with non-zero polarizability in the Rayleigh regime. We verify our theory numerically using exact solutions to Maxwell's equations for first-order Hermite-Gaussian beams, demonstrating single-electron pulse compression factors of $>10^{2}$ in both longitudinal and transverse dimensions with experimentally realizable optical pulses. The proposed scheme is useful in ultrafast electron imaging for both single- and multi-electron pulse compression, and as a means of circumventing temporal distortions in magnetic lenses when focusing ultrashort electron pulses.