Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

TL;DR

This paper demonstrates the use of laser wakefield-accelerated electrons for time-resolved electron diffraction, capturing silicon's structural dynamics on a picosecond scale and paving the way for femtosecond resolution in ultrafast structural studies.

Contribution

It introduces a novel application of laser wakefield-accelerated electrons for ultrafast electron diffraction of crystalline materials.

Findings

Resolved silicon lattice dynamics on a picosecond time scale

Demonstrated deflection of electrons in diffraction peaks using a static magnetic field

Potential for femtosecond temporal resolution in future schemes

Abstract

Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wakefield-accelerated electron bunches for time-resolved electron diffraction measurements of the structural dynamics of single-crystal silicon nano-membranes pumped by an ultrafast laser pulse. In our proof-of-concept study, we resolve the silicon lattice dynamics on a picosecond time scale by deflecting the momentum-time correlated electrons in the diffraction peaks with a static magnetic field to obtain the time-dependent diffraction efficiency. Further improvements may lead to femtosecond temporal resolution, with negligible pump-probe jitter being possible with future laser-wakefield-accelerator ultrafast-electron-diffraction schemes.