摘要
超表面由于具备独特的电磁响应特性,在微波、太赫兹以及光学领域的应用十分广泛.在电磁超表面中构建连续域束缚态(bound states in the continuum,BIC)模式谐振可以产生尖锐的谐振透射峰,因此BIC被广泛用于设计具有高品质因子谐振的超表面.本文实验研究了一种支持准BIC(quasi-BIC,q-BIC)谐振的新型金属太赫兹超表面,通过设计两组金属开口谐振环(split ring resonators,SRRs)的结构参数来调节各自主导的谐振的工作频率,使不同模式谐振之间产生耦合,形成q-BIC模式谐振.并利用电磁场分布及其散射功率的多极分解的计算结果证明了不同模式的共振机制.在入射电磁波分别沿x,y偏振时,通过Jaynes-Cummings模型计算了两模式之间的归一化耦合强度比,分别为0.54%(x偏振)与4.42%(y偏振),解释了不同谐振模式的工作频率随SRRs器件结构参数改变而变化的规律.
Metasurfaces have found extensive applications in microwave,terahertz,and optical range,serving different purposes such as filters,sensors,slow light devices,and nonlinear devices due to their distinctive electromagnetic response characteristics.Recent development requires metasurface devices to exhibit enhanced monochromaticity and stronger light interaction.Consequently,there is a growing interest in designing metasurfaces with high-quality factor(Q-factor)resonances,considering their crucial role in achieving sharp resonances through constructing bound states in the continuum(BIC)mode.The utilization of BIC has emerged as a prominent method of designing metasurfaces with high Q-factor resonances.Due to the fact that the changes in the structural parameters of metasurfaces can simultaneously affect the resonance of two components of q-BICs,it is difficult to achieve on-demand design of operating frequency,bandwidth,and Qfactor.In this work,we investigate a novel THz metasurfaces supporting q-BIC resonance.We optimize the geometric parameters of two split ring resonators(SRRs)to tailor the operating frequencies of intrinsic resonance,and tune the coupling between different resonance modes to form the q-BIC mode resonance.The dominant modes are demonstrated by the results of multipolar decomposition calculations of the electromagnetic field distributions and scattered power at different resonant operating frequencies.In xpolarized and y-polarized incident electromagnetic wave,the normalized coupling strength ratio between the two modes are calculated by Jaynes-Cummings model to be 0.54%(x-polarized)and 4.42%(y-polarized)respectively,which explains the law that the resonant frequency of different modes changes with the structural parameters of SRRs device.In order to analyze the refractive index sensing capabilities of our designed metasurfaces under the incident electromagnetic waves with different polarizations,we investigate the variations of the transmitted spectrum of the metasurface with refractive index of
作者
王玥
王豪杰
崔子健
张达篪
Wang Yue;Wang Hao-Jie;Cui Zi-Jian;Zhang Da-Chi(Key Laboratory of Ultrafast Photoelectric Technology and Terahertz Science in Shaanxi,Xi’an University of Technology,Xi’an 710048,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第5期316-324,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:62275215)
陕西省青年创新团队建设项目(批准号:21JP084)
西安市科技局重点产业链关键核心技术攻关项目(批准号:23LLRH0057)
陕西省重点研发计划(批准号:2023GXLH-038)资助的课题.
关键词
超表面
多极分解
连续域束缚态
太赫兹
metasurfaces
multipole decomposition
bound states in continuum
terahertz
