Terahertz streaking of few-femtosecond relativistic electron beams

TL;DR

This paper demonstrates a novel THz streaking technique for precise time-stamping of ultrashort relativistic electron beams, achieving femtosecond accuracy and enabling significant advancements in ultrafast electron diffraction.

Contribution

It introduces a new THz streaking method for relativistic electron beams, allowing femtosecond-level timing measurement and jitter correction, surpassing previous photoelectron streaking techniques.

Findings

Achieved 1.5 fs (rms) timing accuracy for 6 fs electron pulses.

Demonstrated non-invasive jitter correction method.

Enabled potential sub-10 fs ultrafast electron diffraction.

Abstract

Streaking of photoelectrons with optical lasers has been widely used for temporal characterization of attosecond extreme ultraviolet pulses. Recently, this technique has been adapted to characterize femtosecond x-ray pulses in free-electron lasers with the streaking imprinted by farinfrared and Terahertz (THz) pulses. Here, we report successful implementation of THz streaking for time-stamping of an ultrashort relativistic electron beam of which the energy is several orders of magnitude higher than photoelectrons. Such ability is especially important for MeV ultrafast electron diffraction (UED) applications where electron beams with a few femtosecond pulse width may be obtained with longitudinal compression while the arrival time may fluctuate at a much larger time scale. Using this laser-driven THz streaking technique, the arrival time of an ultrashort electron beam with 6 fs (rms) pulse width has been determined with 1.5 fs (rms) accuracy. Furthermore, we have proposed and demonstrated a non-invasive method for correction of the timing jitter with femtosecond accuracy through measurement of the compressed beam energy, which may allow one to advance UED towards sub-10 fs frontier far beyond the ~100 fs (rms) jitter.