基于人工表面等离激元结构的超表面磁镜  

Magnetic mirror metasurfaces based on spoof surface plasmonic structures

作　　者：殷允桥 吴宏伟 Yin Yun-Qiao;Wu Hong-Wei(School of Mechanics and Photoelectric Physics,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学力学与光电物理学院,淮南232001

出　　处：《物理学报》2020年第23期66-72,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11847002,11904008);中国博士后科学基金(批准号:2019M662132);安徽省自然科学基金(批准号:1908085QA21)资助的课题.

摘　　要：提出了一种表面粗糙磁镜的概念,该界面由人工表面等离激元结构阵列设计而成.这种人工表面等离激元结构通过周期性地将螺旋金属条插入到介电圆盘构造中以支持强磁偶极共振模式.特别地,对于不同外半径下的螺旋结构,可以通过调节每个结构的螺旋度以支持相同共振频率的磁偶极模式.为此,设计了由多种不同尺寸的人工表面等离激元结构排列构成的粗糙磁镜,计算了其效率并与光滑磁镜做了比较.本文所提出的粗糙磁镜可以用来增强光与复杂结构的物质之间的相互作用,亦可能应用于微波和太赫兹波段的生物传感和成像.Mirrors can be seen everywhere in daily life and play an important role in modern optical systems.A traditional mirror,which is made of noble metals,usually has a zero electric field strength and maximal magnetic field strength at its surface induced by the out-of-phase of electric field and in-of-phase of magnetic field between the reflected field and incident field due to the boundary condition of perfect electric conductor.As the magnitude of local electric field determines the strength of the light-matter interaction,it is clear that this interaction is suppressed near the mirror surface.Magnetic mirror,which can enhance electric field on the surface,has been widely applied to strong light-matter interaction for biological sensing,material analysis,and imaging.However,the conventional smooth magnetic mirror with a plane surface is difficult to induce sufficient light-matter interaction when the matter has a complex geometrical shape.Here in this work,we propose a concept of magnetic mirror with a rough interface designed by an array of artificial surface plasmonic structures.The artificial surface plasmonic structure on a subwavelength scale is designed by periodically inserting spiral metallic strips into a dielectric cylinder to support the strong magnetic dipolar resonant mode.The magnetic dipolar resonance of the excited structure is induced by the displacement current circle.Therefore,the resonant frequency is related to the geometrical parameters of the helical structure closely.When we reduce the outer radius of the structure,the magnitude of the displacement current circle will change,resulting in blue-shift of the resonant frequency.At the same time,we also find that increasing the spiral degree of the structure will cause the magnetic dipolar resonance frequency to become red-shifted.Particularly,the same magnetic dipolar mode can be supported in a spiral structure of different size by tuning the spiral degree accordingly.In this context,we design a rough magnetic mirror constructed by the artificia

关 键 词：粗糙磁镜 人工表面等离激元结构 光与物质相互作用 

分 类 号：O441[理学—电磁学] O437[理学—物理]