Terahertz-driven Two-Dimensional Mapping for Electron Temporal Profile Measurement

TL;DR

This paper introduces a novel THz-driven electron oscilloscope that achieves simultaneous high temporal resolution and large measurement window, significantly advancing ultrafast electron and X-ray diagnostics.

Contribution

The authors develop the first THz-driven sampling electron oscilloscope capable of real-time femtosecond electron measurement with an extended temporal window.

Findings

Achieves sub-cycle THz electron sampling with tens-of-picosecond window

Surpasses previous THz techniques by an order of magnitude in temporal window

Enhances measurement through projection imaging and signal magnification

Abstract

The precision measurement of real-time electron temporal profiles is crucial for advancing electron and X-ray devices used in ultrafast imaging and spectroscopy. While high temporal resolution and large temporal window can be achieved separately using different technologies, real-time measurement enabling simultaneous high resolution and large window remains challenging. Here, we present the first THz-driven sampling electron oscilloscope capable of measuring electron pulses with high temporal resolution and a scalable, large temporal window simultaneously. The transient THz electric field induces temporal electron streaking in the vertical axis, while extended interaction along the horizontal axis leads to a propagation-induced time delay, enabling electron beam sampling with sub-cycle THz wave. This allows real-time femtosecond electron measurement with a tens-of-picosecond window, surpassing previous THz-based techniques by an order of magnitude. The measurement capability is further enhanced through projection imaging, deflection cavity tilting, and shorted antenna utilization, resulting in signal spatial magnification, extended temporal window, and increased field strength. The technique holds promise for a wide range of applications and opens new opportunities in ultrafast science and accelerator technologies.