Ultrashort electron pulse generation with single-femtosecond-level jitter.

Ultrashort electron bunches with precise pump laser synchronization and adequate charge are fundamental for time-resolved techniques like ultrafast electron diffraction (UED) and advanced light sources. Here, we achieve electron chopping and compression through a single terahertz (THz)-driven device, producing 50-femtosecond, near-femtocoulomb (fC) electron pulses with 1.4-femtosecond arrival time jitter sustained over an hour. This achieves a 35-fold pulse duration reduction and 10-fold jitter improvement compared to cases without the THz device, marking the shortest directly measured pulse duration and smallest timing jitter reported for multielectron pulses (near-fC level) at the kilo-electron volt level. High-quality electron diffraction confirms this technique's suitability for UED. We further introduce a beam tilting correction via a tilted antenna, enabling bunch compression down to 6 femtoseconds. Furthermore, we have demonstrated its capability of reducing extended timing jitter from several hundred femtoseconds to the few-femtosecond level, offering a promising solution to the long-standing synchronization challenge between radio frequency accelerators and optical lasers. This advancement paves the way for jitter-free UED techniques with attosecond temporal resolution, thereby notably enhancing modern ultrafast applications.