德国罗斯托克大学E. Goulielmakis课题组报道发现了阿秒场发射。这一研究成果于2023年1月25日发表在国际顶尖学术期刊《自然》上。

研究人员利用强的亚周期光瞬态从钨纳米尖端诱导电子脉冲的光场发射，并利用同一瞬态的弱复制品直接实时研究发射动力学。获取从尖端表面散射的电子脉冲的时间属性，包括持续时间τ=(53as±5as)和啁啾，以及对纳米尺度近场的直接探索，为阿秒物理和纳米光学界面的研究和应用开辟了新的前景。

据介绍，电子场发射是科学技术取得巨大进步的基础，从频率越来越高的信号处理到以皮米分辨率对物质原子尺度结构进行成像。电子显微镜技术的进步使物质在电子动力学的空间(皮米)和时间(阿秒)尺度上的完全可视化成为可能，要求技术能够限制和检查亚飞秒时间间隔上的场发射。强激光脉冲通过演示飞秒限制和亚光周期控制，为纳米结构金属的光场发射铺平了道路。然而，阿秒电子脉冲的测量仍然没有定论。

附：英文原文

Title: Attosecond field emission

Author: Kim, H. Y., Garg, M., Mandal, S., Seiffert, L., Fennel, T., Goulielmakis, E.

Issue&Volume: 2023-01-25

Abstract: Field emission of electrons underlies great advances in science and technology, ranging from signal processing at ever higher frequencies1 to imaging of the atomic-scale structure of matter2 with picometre resolution. The advancing of electron microscopy techniques to enable the complete visualization of matter on the native spatial (picometre) and temporal (attosecond) scales of electron dynamics calls for techniques that can confine and examine the field emission on sub-femtosecond time intervals. Intense laser pulses have paved the way to this end3,4 by demonstrating femtosecond confinement5,6 and sub-optical cycle control7,8 of the optical field emission9 from nanostructured metals. Yet the measurement of attosecond electron pulses has remained elusive. We used intense, sub-cycle light transients to induce optical field emission of electron pulses from tungsten nanotips and a weak replica of the same transient to directly investigate the emission dynamics in real time. Access to the temporal properties of the electron pulses rescattering off the tip surface, including the duration τ=(53as±5as) and chirp, and the direct exploration of nanoscale near fields open new prospects for research and applications at the interface of attosecond physics and nano-optics.

DOI: 10.1038/s41586-022-05577-1

Source: https://www.nature.com/articles/s41586-022-05577-1