Free-electron interactions with van der Waals heterostructures: a source of focused X-ray radiation  

作　　者：Xihang Shi Yaniv Kurman Michael Shentcis Liang Jie Wong F.Javier Garcia de Abajo ldo Kaminero 

机构地区：[1]Solid State Institute and Faculty of Electrical and Computer Engineering,Technion-Israel Institute of Technology,Haifa 32000,Israel [2]School of Electrical and Electronic Engineering,Nanyang Technological University Singapore 639798,Singapore [3]ICFO-Institut de Ciencies Fotoniques,The Barcelona Institute of Science and Technology,Castelldefels 08860,Spain [4]iCREA-lnstitucio Catalana de Recerca i Estudis Avangats,Passeig Lluis Companys23,Barcelona08010,Spain

出　　处：《Light(Science & Applications)》2023年第7期1370-1380,共11页光（科学与应用)（英文版）

基　　金：supported by the ERC(Starter Grant No.851780)and the BSF(Grant No.2018288);the support of the National Research Foundation(Project ID NRF2020-NRF-ISF004-3525);the Nanyang Assistant Professorship Start-up Grant.FJ.G.d.A.acknowledges support from the Spanish MICINN(PID2020-112625GB-100 and Severo Ochoa CEX2019-000910-S),ERC(Advanced Grant No.789104-eNANO);the Catalan CERCA Program,and Fundacio Privada Cellex.X.S.is supported in part by a fellowship of the Israel Council for Higher Education and by the Technion's Helen Diller Quantum Center.

摘　　要：The science and technology of X-ray optics have come far,enabling the focusing of X-rays for applications in highresolution X-ray spectroscopy,imaging,and irradiation.In spite of this,many forms of tailoring waves that had substantial impact on applications in the optical regime have remained out of reach in the X-ray regime.This disparity fundamentally arises from the tendency of refractive indices of all materials to approach unity at high frequencies,making X-ray-optical components such as lenses and mirrors much harder to create and often less effcient.Here,we propose a new concept for X-ray focusing based on inducing a curved wavefront into the X-ray generation process,resulting in the intrinsic focusing of X-ray waves.This concept can be seen as effectively integrating the optics to be part of the emission mechanism,thus bypassing the effciency limits imposed by X-ray optical components,enabling the creation of nanobeams with nanoscale focal spot sizes and micrometer-scale focal lengths.Specifically,we implement this concept by designing aperiodic vdw heterostructures that shape X-rays when driven by free electrons.The parameters of the focused hotspot,such as lateral size and focal depth,are tunable as a function of an interlayer spacing chirp and electron energy.Looking forward,ongoing advances in the creation of many-layer vdw heterostructures open unprecedented horizons of focusing and arbitrary shaping of X-ray nanobeams.

关 键 词：OPTICS integrating ARBITRARY 

分 类 号：O43[机械工程—光学工程]