Tunable photon-induced spatial modulation of free electrons

TL;DR

This paper demonstrates tunable, photon-induced spatial modulation of free electrons via surface plasmon polaritons, enabling dynamic electron wavefront shaping with potential applications in nanolithography, imaging, and material analysis.

Contribution

It introduces a method for externally controlling electron beam patterns using surface plasmon polaritons, including the first observation of 2D spatial Rabi oscillations.

Findings

Achieved dynamic control of electron distributions using SPP pattern shaping

Observed 2D spatial Rabi oscillations in electron beams

Generated electron features below the SPP wavelength

Abstract

Spatial modulation of electron beams is an essential tool for various applications such as nanolithography and imaging, yet its implementations are severely limited and inherently non-tunable. Conversely, light-driven electron spatial modulation could potentially allow arbitrary electron wavefront shaping via the underlying mechanism of photon-induced near-field electron microscopy (PINEM). Here, we present tunable photon-induced spatial modulation of electrons through their externally-controlled interaction with surface plasmon polaritons (SPPs). Using recently developed methods of shaping SPP patterns, we demonstrate a dynamic control of the electron beam with a variety of high-quality electron distributions. Intriguingly, by utilizing the intrinsic interaction nonlinearity, we attain the first observation of 2D spatial Rabi oscillations and generate electron features below the SPP wavelength. Our work paves the way to on-demand electron wavefront shaping at ultrafast timescales, with prospects for aberration correction, nano-fabrication and material characterization.