二维太赫兹拓扑光子晶体的远场探测  

Far-field detection of two-dimensional terahertz topological photonic crystals

作　　者：马家军 欧阳春梅[1] 陈勰宇 许全 李绍限 冯汐 牛力 刘艺[1] 韩家广[1] 张伟力 MA JiaJun;OUYANG ChunMei;CHEN XieYu;XU Quan;LI ShaoXian;FENG Xi;NIU Li;LIU Yi;HAN JiaGuang;ZHANG WeiLi(Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering,and the Key Laboratory of Optoelectronics Information and Technology(Ministry of Education),Tianjin University,Tianjin 300072,China;School of Electrical and Computer Engineering,Oklahoma State University,Stillwater 74078,USA)

机构地区：[1]天津大学太赫兹研究中心,精密仪器与光电子工程学院,光电信息技术教育部重点实验室,天津300072 [2]俄克拉荷马州立大学电气和计算机工程学院,美国斯蒂尔沃特74078

出　　处：《中国科学：物理学、力学、天文学》2021年第5期64-70,共7页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:61775159,61735012,61875150,61805129,61605143);国家重点基础研究发展计划(编号:2017YFA0701004)资助项目。

摘　　要：随着量子霍尔效应(QHE)在凝聚态物理中的深入研究,一类具有非平庸特性的新型材料——拓扑绝缘体引起了人们极大的兴趣.与此同时,随着人工超材料的发展,一种可以产生新型单向传输模式且无背散射的拓扑光子晶体(Topological Photonic Crystals)引起非常大的关注.在本文中,根据时空反演对称性和量子自旋霍尔效应(QSHE)理论,我们构建了一个工作频率在太赫兹波段的拓扑光子晶体,当扩展或压缩六角蜂窝状晶格时,空间反演对称性会被打破,从而打破能带简并实现光子能隙结构,将具有相反拓扑特性的光子晶体摆放在一起,在它们的交界面可实现具有单向传输且不受缺陷影响的拓扑边界态.本文在太赫兹波段实验表征了该拓扑光子晶体的反射谱特性,发现扩展和压缩六角蜂窝状晶格获得的拓扑光子晶体的反射谷频率分别对应他们各自第一能带p±在Г点处的频率,由此可得知光子能隙的宽度,为拓扑光子晶体的验证提供了新的手段.Originating from the investigation of condensed matter states,we have discovered a new material with phase transition no-trivial properties——topological insulators.With the progress in artificial metamaterials,the photonic crystals which can give rise to topological edge states that propagate around sharp corners immune to scattering have captured much attention.In this paper,according to the spatial and time reversal symmetry and quantum spin Hall effect theory,we presented a topological photonic crystal made of metallic cylinders at terahertz frequencies.By slightly expanding and shrinking the unit cell,the spatial reversal symmetry was broken and therefore,the band degeneracy was broken,realizing the topological band gap.Unidirectional topological edge states were proven to exist on a domain wall connecting two photonic crystals with opposite topological properties without back-scattering.Then we investigated the reflection spectra of the designed topological photonic crystals in the terahertz regime,which provided a new means to verify topological photonic crystals.

关 键 词：拓扑 光子晶体 量子自旋霍尔效应 边界态 反射谱 

分 类 号：O734[理学—晶体学] TB34[一般工业技术—材料科学与工程]