# Laser-Driven Electron Lensing in Silicon Microstructures

## TL;DR

This paper presents a novel laser-driven electron lens in silicon microstructures, tunable by laser intensity, capable of focusing electrons with high gradients and variable focal lengths, advancing electron optics technology.

## Contribution

The work introduces a monolithic silicon-based, laser-tunable electron lens with high focusing gradients and adjustable focal lengths, demonstrating a new approach in electron beam manipulation.

## Key findings

- Achieved a focal length of 50 μm with 100 MV/m laser fields.
- Demonstrated tunability of the lens from 21 μm to several centimeters.
- Measured focusing gradients up to 1.4 MT/m.

## Abstract

We demonstrate a laser-driven, tunable electron lens fabricated in monolithic silicon. The lens consists of an array of silicon pillars pumped symmetrically by two 300 fs, 1.95 $\mu$m wavelength, nJ-class laser pulses from an optical parametric amplifier. The optical near-field of the pillar structure focuses electrons in the plane perpendicular to the pillar axes. With 100 $\pm$ 10 MV/m incident laser fields, the lens focal length is measured to be 50 $\pm$ 4 $\mu$m, which corresponds to an equivalent quadrupole focusing gradient $B'$ of 1.4 $\pm$ 0.1 MT/m. By varying the incident laser field strength, the lens can be tuned from a 21 $\pm$ 2 $\mu$m focal length ($B'>3.3$ MT/m) to focal lengths on the cm-scale.