近日，德国欧洲X射线自由电子激光装置（XFEL）的Jiawei Yan及其研究团队取得一项新进展。经过不懈努力，他们研制出高重复率太瓦-阿秒硬X射线自由电子激光器。相关研究成果已于2024年11月25日在国际知名学术期刊《自然—光子学》上发表。
本研究报道了利用特殊工作模式下的自由电子激光器产生太瓦量级阿秒硬X射线脉冲的方法。研究人员实现了9千电子伏特的单峰X射线脉冲，平均脉冲能量约为180微焦耳，比以往报道高出一个多数量级，估计的平均脉冲持续时间为半高全宽200阿秒。
利用欧洲XFEL的独特能力——每秒可输送十个脉冲序列，每个序列包含以兆赫兹重复率发射的数百个脉冲——本研究展示了以2.25兆赫兹重复率产生阿秒X射线脉冲的过程。这些高强度、高重复率的阿秒X射线脉冲为结构和电子无损伤X射线测量以及阿秒时间分辨X射线方法带来了变革性的前景，预示着超快X射线科学新时代的到来。
据悉，埃米（Angstrom）和阿秒（attosecond）是描述各种材料中电子动力学的基本时空尺度。尽管预期波长与原子尺度相当的阿秒脉冲，将成为推动阿秒科学发展的关键工具，但产生具有埃级波长的高功率硬X射线阿秒脉冲仍然是一项艰巨的挑战。
附：英文原文
Title: Terawatt-attosecond hard X-ray free-electron laser at high repetition rate
Author: Yan, Jiawei, Qin, Weilun, Chen, Ye, Decking, Winfried, Dijkstal, Philipp, Guetg, Marc, Inoue, Ichiro, Kujala, Naresh, Liu, Shan, Long, Tianyun, Mirian, Najmeh, Geloni, Gianluca
Issue&Volume: 2024-11-25
Abstract: Angstrom and attosecond are the fundamental spatiotemporal scales for electron dynamics in various materials. Although attosecond pulses with wavelengths comparable to the atomic scales are expected to be a key tool in advancing attosecond science, producing high-power hard X-ray attosecond pulses at ngstrom wavelengths remains a formidable challenge. Here, we report the generation of terawatt-scale attosecond hard X-ray pulses using a free-electron laser in a special operation mode. We achieved 9keV single-spike X-ray pulses with a mean pulse energy of around 180μJ, exceeding previous reports by more than an order of magnitude, and an estimated average pulse duration of 200as at full-width at half-maximum. Exploiting the unique capability of the European XFEL, which can deliver ten pulse trains per second with each containing hundreds of pulses at megahertz repetition rates, this study demonstrates the generation of attosecond X-ray pulses at a 2.25MHz repetition rate. These intense high-repetition-rate attosecond X-ray pulses present transformative prospects for structural and electronic damage-free X-ray measurements and attosecond time-resolved X-ray methodologies, heralding a new era in ultrafast X-ray science.
DOI: 10.1038/s41566-024-01566-0
Source: https://www.nature.com/articles/s41566-024-01566-0