基于准连续域束缚态的强圆二色性超表面  

Strong circular dichroism chiral metasurfaces generated by quasi bound state in continuum domain

作　　者：夏兆生 刘宇行 包正 王丽华 吴博[1,2] 王刚 王辉[3] 任信钢 黄志祥[1,2] Xia Zhao-Sheng;Liu Yu-Hang;Bao Zheng;Wang Li-Hua;Wu Bo;Wang Gang;Wang Hui;Ren Xin-Gang;Huang Zhi-Xiang(Key Laboratory of Intelligent Computing&Signal Processing,Ministry of Education,Anhui University,Hefei 230601,China;Information Materials and Intelligent Sensing Laboratory of Anhui Province,Institute of Physical Science and Information Technology,Anhui University,Hefei 230601,China;Anhui Province Key Laboratory of Simulation and Design for Electronic Information System,Hefei Normal University,Hefei 230001,China)

机构地区：[1]安徽大学,计算智能与信号处理教育部重点实验室,合肥230601 [2]安徽大学,信息材料与智能感知安徽省实验室,合肥230601 [3]合肥师范学院,电子信息系统仿真设计安徽省重点实验室,合肥230001

出　　处：《物理学报》2024年第17期285-293,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62171001,U20A20164,U22A2017,61871001,61701001,61971001,6140209);国家重点研发计划(批准号:2022YFB4200901-1,2022YFB4200903);安徽省自然科学基金(批准号:2108085MF198,1908085QF251);安徽省高校协同创新计划(批准号:GXXT-2022-009,GXXT-2020-050,GXXT-2020-051,GXXT-2021-027,GXXT-2021-037);安徽省博士后科学基金创建项目(批准号:2019B348);安徽省级科技重大项目(公开竞赛类)项目计划(批准号:202203a05020035);安徽省新型半导体材料专用功率器件工程技术研究中心开放基金(批准号:2021GCYJZX02)资助的课题.

摘　　要：连续域束缚态最初是在量子力学中发现的,它是一种可保持局域化的波动现象.这种效应已在各种材料系统中得到广泛研究,包括压电材料、石墨烯和光子晶体.本工作提出了一种由中断的环形槽组成的四重旋转对称硅超表面.通过同时打破晶胞的面内反转对称性,实现了具有高品质因子和显著手性的准连续域束缚态.通过对动量空间中拓扑荷的研究,揭示了由超表面的内部共振机制产生的准连续域束缚态的独特拓扑特征.在合适的对称破坏下,具有平面内对称破坏的四重旋转对称超表面表现出–0.93的强圆二色性,并且其显示出了在对称破坏较大时的强圆二色性.这项工作所取得的成果在手性生物传感器和低阈值激光器等领域具有广阔的应用前景.Bound states in the continuum(BIC)were initially observed in quantum mechanics as a phenomenon capable of maintaining localized wave behavior.This effect has been extensively studied across various material systems,including piezoelectric materials,graphene,and photonic crystals.Recently,the BIC mode has employed to achieve strong optical chirality in metamaterials with symmetry breaking.In this work,we propose a silicon metasurface with an interrupted ring groove,which has a fourfold rotationally symmetry.By breaking the in-plane inversion symmetry of the unit cell,we achieve quasi-BICs with the high quality factor and conspicuous chirality.Moreover,by analyzing topological charges in momentum space,we reveal that the unique topological characteristics of quasi-BIC are generated by the internal resonance of metasurface.When the symmetry breaking reaches a certain level,our proposed symmetry-broken metasurface shows a strong circular dichroism and its value is–0.93,which indicates that the quasi-BIC mode can has a strong chiral selectivity.For chiral sensing applications,the chiral metasurface exhibits a spectral resolution of approximately 0.003.The findings presented in this work have great potential applications in chiral sensing,nonlinear chiral optics,low-threshold lasers,and other related fields.

关 键 词：连续域束缚态 超表面 手性 品质因子 

分 类 号：O43[机械工程—光学工程]