狭缝阵列法产生准贝塞尔电子束用于HAADF-STEM成像研究
林宇铖，陈鑫铠，张婉如，田 鹤*
(1.浙江大学电子显微镜中心，硅材料国家重点实验室，材料科学与工程学院，浙江 杭州 310027)
摘 要 贝塞尔电子束具有的自愈性和无衍射性使其在电子显微成像和电子断层扫描等领域中具有独特优势。本文制备了狭缝阵列光阑并安装在透射电子显微镜中用于产生具有自愈性和无衍射性的准贝塞尔电子束(Bessel beams, BBs)。与单狭缝法相比，狭缝阵列光阑(slit arrays aperture, SAA)法提高了BBs的中心束强度并降低衍射旁瓣影响。与普通会聚束相比，BBs被用于扫描透射模式(scanning transmission electron microscopy, STEM)下的高角环形暗场像(high-angle annular dark-field, HAADF)，成像时具有更大景深并能修正强度与厚度间的非线性阻尼效应，因而BBs将在易损伤样品拍摄和电子断层扫描中拥有较好的应用前景。
关键词 狭缝阵列光阑；贝塞尔电子束；HAADF-STEM
中图分类号：TB383.1；TN16
文献标识码：A doi:10.3969/j.issn.1000-6281.2024.04.006
Generation of quasi electron Bessel beams by slit arrays for HAADF-STEM imaging
LIN Yu-cheng1, CHEN Xin-kai1, ZHANG Wan-ru1, TIAN He1*
(1.Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou Zhejiang 310027, China)
Abstract Bessel electron beams have unique advantages in electron microscopy imaging and tomography due to its self-healing and non-diffraction properties. The slit arrays aperture is prepared and installed in transmission electron microscope to generate quasi Bessel beams (BBs). In this paper, it is verified that the slit arrays method produces non-diffracting and self-healing electron beams. Compared with the single slit method, the center beam intensity of BBs is increased and the influence of side lobes intensity is reduced. It is proved that BBs has larger depth of field and can correct the nonlinear damping effect between intensity and thickness when used in HAADF-STEM imaging compared with ordinary converging beam. Therefore, BBs will have a good application prospect in the imaging of vulnerable samples and electron tomography.
Keywords slit arrays aperture; electron Bessel beams; HAADF-STEM
[1] 杨性愉, 宋继恩. Bessel光束的传输模型(英文)[J]. 光电子. 激光, 2002, 13(8): 4.
[2] ARLT J, GARCES-CHAVEZ V, SIBBETT W, et al. Optical micromanipulation using a Bessel light beam[J]. Optics Communications, 2001, 197(4/5/6): 239-245.
[3] VOLKE-SEPULVEDA K, GARCES-CHAVEZ V, CHAVEZ-CERDA S, et al. Orbital angular momentum of a high-order Bessel light beam[J]. Journal of Optics B Quantum and Semiclassical Optics, 2002, 4(2): 82-89.
[4] RONG C, ZHAO Y, WANG Y, et al. 3D super resolution microscopy in multicellular tissues[C]// Conference on Lasers and Electro-Optics/Pacific Rim, 2018.
[5] ISHIDA T, OWAKI T, OHTSUKA M, et al. Extension of focal depth by electron quasi-Bessel beam in atomic-resolution scanning transmission electron microscopy[J]. Applied Physics Express, 2022, 15(11): 115001.
[6] LEBEAU J M, STEMMER S. Experimental quantification of annular dark-field images in scanning transmission electron microscopy[J]. Ultramicroscopy, 2008, 108(12): 1653–1658.
[7] VAN DEN BROEK W, ROSENAUER A, GORIS B, et al. Correction of non-linear thickness effects in HAADF STEM electron tomography[J]. Ultramicroscopy, 2012, 116: 8–12.
[8] ROSENAUER A, GRIES K, MULLER K, et al. Measurement of specimen thickness and composition in AlxGa1-XN/GaN using high-angle annular dark field images[J]. Ultramicroscopy, 2009, 109(9): 1171–1182.
[9] MARTINEZ G T, JONES L, DE BACKER A, et al. Quantitative STEM Normalisation: The importance of the electron flux[J]. Ultramicroscopy, 2015, 159: 46–58.
[10] YANG P, LI Z, YANG Y, et al. Effects of electron microscope parameters and sample thickness on high angle annular dark field imaging[J]. Scanning, 2022, 2022: 1–9.
[11] VICENTE O C, CALOZ C. Bessel beams: A unified and extended perspective[J]. Optica, 2021, 8(4)：451.
[12] GRILLO V, KARIMI E, GAZZADI G C, et al. Generation of nondiffracting electron Bessel beams[J]. Physical Review X, 2014, 4(1): 011013.
[13] GRILLO V, HARRIS, J, GAZZADI G C, et al. Generation and application of Bessel beams in electron microscopy[J]. Ultramicroscopy, 2016, 166: 48–60.
[14] HETTLER S, GRÜNEWALD L, MALAC M. Quasi non-diffractive electron Bessel beams using direct phase masks with applications in electron microscopy[J]. New Journal of Physics, 2019, 21(3): 033007.
[15] GRÜNEWALD L, GERTHSEN D, HETTLER S. Fabrication of phase masks from amorphous carbon thin films for electron-beam shaping[J]. Beilstein Journal of Nanotechnology, 2019, 10: 1290–1302.
[16] ZHENG C, PETERSEN T C, KIRMSE H, et al. Axicon lens for electrons using a magnetic vortex: The efficient generation of a Bessel beam[J]. Physical Review Letters, 2017, 119(17): 174801.
[17] SAITOH K, HIRAKAWA K, NAMBU H, et al. Generation of electron Bessel beams with nondiffractive spreading by a nanofabricated annular slit[J]. Journal of the Physical Society of Japan, 2016, 85(4): 043501.
[18] 吴平辉. Bessel光束的机理及方法研究[D]. 浙江大学, 2016.
[19] R HARVEY T, S PIERCE J, K AGRAWAL A, et al. Efficient diffractive phase optics for electrons[J]. New Journal of Physics, 2014, 16(9): 093039.
[20] HUA X, GUO C, WANG J, et al. Depth-extended, high-resolution fluorescence microscopy: Whole-cell imaging with double-ring phase (DRiP) modulation[J]. Biomedical Optics Express, 2019, 10(1): 204.
[21] 沈若涵, 明文全, 何玉涛, 等. 景深对HAADF-STEM原子分辨率三维重构的影响[J]. 电子显微学报, 2020, 39(5): 526-535.
[22] LUPINI A R, DE JONGE N. The Three-dimensional point spread function of aberration-corrected scanning transmission electron microscopy[J]. Microscopy and Microanalysis, 2011, 17(5): 817–826.
[23] 王文龙, 华旭宏, 王克彦, 等. 虚焦图像的模糊度检测方法及装置[P]. 中国, 发明专利, CN202010085147.0. 2020.
[24] NISHI R, MORIYAMA Y, YOSHIDA K, et al. An autofocus method using quasi-gaussian fitting of image sharpness in ultra-high-voltage electron microscopy[J]. Microscopy, 2013, 62(5): 515–519.
[25] HAYASHIDA M, MALAC M. Practical electron tomography guide: Recent progress and future opportunities[J]. Micron, 2016, 91: 49–74.
[26] DAHMEN T, TRAMPERT P, de JONGE N, et al. Advanced recording schemes for electron tomography[J]. MRS Bulletin, 2016, 41(7): 537–541.
