A design for terahertz-driven isolated sub-femtosecond electron pulses

• Published in: Applied physics express Vol. 18; no. 7; pp. 72001 - 72005
• Main Authors: Zhu, Songyu, Zeng, Yushan, Yu, Xieqiu, Zhong, Hui, Fu, Xuewen, Song, Liwei, Tian, Ye, Xu, Zhizhan
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.07.2025
• Subjects: field enhancement; high-field terahertz wave; ultrafast electron pulses
• ISSN: 1882-0778; 1882-0786
• DOI: 10.35848/1882-0786/ade6c1

Isolated electron pulses are pivotal in resolving ultrafast dynamics, especially in the sub-optical-cycle regime. While recent advancements in ultrafast electron microscopy have brought the ultimate duration of electron pulses to the attosecond scale, the associated pulse train at optical repetition rates challenges time-solved study with relatively long relaxation time. To address this issue, we present a terahertz-driven deflector-based system capable of achieving sub-femtosecond pulse durations. Unlike radio frequency which requires cumbersome cavities, our numerical simulations demonstrate that terahertz field enhancement within a thin metal foil could enable pulse slicing of isolated electron pulses as short as 817 attoseconds from a 500-fs pulse. The design can also be extended to a direct current with two additional capacitors. We analyze key design parameters of our design to provide empirical guidance for experimental implementations, with the potential of delivering ultrafast single electron pulses compactly and cost-effectively.