Optical skyrmions are structured vector fields with nontrivial polarization topology and subwavelength-scale features. One common approach to generating optical skyrmions is the superposition of a zeroth-order Bessel beam and a higher-order Bessel beam carrying orbital angular momentum, with each beam possessing an orthogonal circular polarization state. However, creating such complex beams typically requires bulky free-space optical setups; therefore, recent efforts have focused on compact optical skyrmion generators based on metasurfaces. Nevertheless, achieving the degrees of freedom required for simultaneous phase and polarization control remains challenging because of the limited design flexibility of conventional meta-atoms. Here, we address this challenge by employing an inverse-design approach and demonstrate a single-layer metasurface that generates high-fidelity optical skyrmions. We employ an adjoint-based topology-optimization method to design a silicon metasurface that converts an incident beam into an optical skyrmion without the need for additional optical components. The optimized metasurface generates an optical skyrmion with skyrmion number $(N_\mathrm{sk}) = 0.970$. This work demonstrates that inverse design can be a promising route to compact skyrmion generators, and our approach provides a basis for near-field particle manipulation and the generation of independent topological bits in dense photonic integration.
University of Southern Denmark（南丹麦大学）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；L.F. Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences（俄罗斯科学院L.F.韦列夏金高压物理研究所）；GREMAN, CNRS, UMR 7347, INSA CVL, Université de Tours（图尔大学GREMAN实验室）
Plasmonic Metasurfaces for Magnetic Skyrmion Control via the Inverse Faraday Effect
Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP（索邦大学，法国国家科学研究中心，巴黎纳米科学研究所）；School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology（大连理工大学光电工程与仪器科学学院）；Instituto de Engenharia de Sistemas E Computadores – Microsistemas e Nanotecnologias (INESC MN)（系统计算机工程研究所-微系统与纳米技术）；Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain（天主教鲁汶大学凝聚态与纳米科学研究所）；School of Electronic and Information Engineering, Ningbo University of Technology（宁波理工学院电子与信息工程学院）；Blackett Laboratory, Department of Physics, Imperial College London（伦敦帝国理工学院物理系布莱克特实验室）；London Centre for Nanotechnology, Imperial College London（伦敦帝国理工学院伦敦纳米技术中心）；Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay（巴黎萨克雷大学CNRS-Thales阿尔伯特·费尔特实验室）
State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University（浙江大学光电科学与工程学院）；School of Physics, University of the Witwatersrand（威特沃特斯兰德大学物理学院）
Ultrawide-angle diffraction-limited 2D beam steering via hybrid integrated metasurface-photonic circuit
Massachusetts Institute of Technology（麻省理工学院）；Pi Inc.（2Pi公司）；Singapore-MIT Alliance for Research and Technology (SMART)（新加坡-麻省理工学院研究与技术联盟）；University of Maryland, College Park（马里兰大学帕克分校）；NASA Langley Research Center（美国国家航空航天局兰利研究中心）；Korea Advanced Institute of Science and Technology（韩国科学技术院）
Four-channel Imaging Based on Reconfigurable Metasurfaces: Hyperchaotic Encryption under Physical Protection
School of Information Engineering, Nanchang University（南昌大学信息工程学院）；Institute for Advanced Study, Nanchang University（南昌大学高等研究院）；Jiluan Academy, Nanchang University（南昌大学极链学院）
Defects encode high-dimensional topological information
University of Oxford（牛津大学）；Institute of Photonics Technology, Jinan University（暨南大学光子技术研究所）；University of Southampton（南安普顿大学）；Tsinghua Shenzhen International Graduate School, Tsinghua University（清华大学深圳国际研究生院）；Nanhu Laser Laboratory（南湖激光实验室）
High-efficiency infrared upconversion imaging with nonlinear silicon metasurfaces empowered by quasi-bound states in the continuum
Nanchang University（南昌大学）；Institute for Advanced Study, Nanchang University（南昌大学高等研究院）；School of Education, Nanchang Institute of Science and Technology（南昌理工学院教育学院）；Guangdong Polytechnic Normal University（广东技术师范大学）
Inverse Design of Realizable Metasurface based Absorbers using Improved Conditioning and Diversity Enhanced Progressively Growing GANs
Centre for Electromagnetics, CSIR-National Aerospace Laboratories（电磁研究中心，国家航空航天实验室）；Birla Institute of Technology and Science, Pilani, Rajasthan（比拉理工学院和科学学院，比里尼）；Indian Institute of Technology, Bombay, Maharashtra（孟买印度理工学院，马哈拉施特拉）
Inverse Design of Tunable Infrared Metasurface Absorbers via a Conditional Wasserstein Generative Adversarial Network
State Key Laboratory of Integrated Service Networks, Xidian University（西安电子科技大学集成服务网络国家重点实验室）；Air Defense and Antimissile School, Air Force Engineering University（空军工程大学防空反导学院）；Inter disciplinary Center for Quantum Information, College of Information Science and Electronic Engineering, Zhejiang University（浙江大学信息与电子工程学院量子信息交叉研究中心）
Tensor-Engineered Van der Waals NbOCl2 Resonant Metasurface for Polarization-entangled Bell State Generation
CAS Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology（中国科学院纳米科技标准化与计量重点实验室，国家纳米科学中心）；Frontiers Science Center for New Organic Matter, Tianjin Key Lab for Rare Earth Materials and Applications, Renewable Energy Conversion and Storage Center (RECAST), School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University（前沿科学中心新有机物质，天津市稀土材料与应用重点实验室，可再生能源转换与存储中心（RECAST），南开大学材料科学与工程学院，先进材料国家研究院）；CAS Key Laboratory of Quantum Information, University of Science and Technology of China（中国科学院量子信息重点实验室，中国科学技术大学）；School of Materials Science and Engineering, Peking University（北京大学材料科学与工程学院）；School of Materials Science and Engineering, Nanyang Technological University（南洋理工大学材料科学与工程学院）；School of Electrical and Electronic Engineering, Nanyang Technological University（南洋理工大学电气与电子工程学院）；University of Chinese Academy of Sciences（中国科学院大学）；Hefei National Laboratory, University of Science and Technology of China（合肥国家实验室，中国科学技术大学）；Beijing Key Laboratory of Advanced Micro- and Nanoscale Light Source Materials and Devices, Peking University（北京先进微纳光源材料与器件重点实验室，北京大学）
An integrated super resolution THz 3D imaging system based on a linear nonlocal achromatic freeform Bessel beam lens and high power oscillator radiator array
City University of Hong Kong（香港城市大学）；Southeast University（东南大学）
