Attosecond Electron Pulse Trains and Quantum State Reconstruction in Ultrafast Transmission Electron Microscopy

TL;DR

This paper presents a novel method for preparing, controlling, and characterizing free-electron quantum states using optical fields, enabling attosecond pulse trains and quantum state tomography for ultrafast electron microscopy.

Contribution

It introduces a new framework for electron quantum state manipulation and a quantum state tomography technique called SQUIRRELS, advancing ultrafast electron microscopy capabilities.

Findings

Demonstrated attosecond electron pulse trains in microscopy.

Developed SQUIRRELS for reconstructing electron density matrices.

Showed potential for nanoscale electron-matter entanglement studies.

Abstract

We introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond pulse trains for electron microscopy. Specifically, we employ phase-locked single-color and two-color optical fields to coherently control the electron wave function along the beam direction. We establish a new variant of quantum state tomography - "SQUIRRELS" - to reconstruct the density matrices of free-electron ensembles and their attosecond temporal structure. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and the development of new forms of ultrafast electron microscopy and spectroscopy down to the attosecond regime.