Free-Electron Shaping Using Quantum Light

TL;DR

This paper demonstrates that using quantum light instead of classical laser fields can enhance control over free-electron pulse shaping, compression, and statistics, enabling advanced electron microscopy and ultrafast material studies.

Contribution

It introduces a novel approach of employing quantum light for electron pulse shaping, revealing effects like accelerated compression with phase-squeezed light and ultrashort double pulses from amplitude squeezing.

Findings

Phase-squeezed light accelerates electron pulse compression.

Amplitude squeezing produces ultrashort double-pulse electron profiles.

Electron coherence depends on the quantum statistics of the modulating light.

Abstract

Controlling the wave function of free electrons is important to improve the spatial resolution of electron microscopes, the efficiency of electron interaction with sample modes of interest, and our ability to probe ultrafast materials dynamics at the nanoscale. In this context, attosecond electron compression has been recently demonstrated through interaction with the near fields created by scattering of ultrashort laser pulses at nanostructures followed by free electron propagation. Here, we show that control over electron pulse shaping, compression, and statistics can be improved by replacing coherent laser excitation by interaction with quantum light. We find that compression is accelerated for fixed optical intensity by using phase-squeezed light, while amplitude squeezing produces ultrashort double-pulse profiles. The generated electron pulses exhibit periodic revivals in complete analogy to the optical Talbot effect. We further reveal that the coherences created in a sample by interaction with the modulated electron are strongly dependent on the statistics of the modulating light, while the diagonal part of the sample density matrix reduces to a Poissonian distribution regardless of the type of light used to shape the electron. The present study opens a new direction toward the generation of free electron pulses with additional control over duration, shape, and statistics, which directly affect their interaction with a sample.