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物理学院“博约学术论坛”系列报告( 第255期)

发布日期:2020年07月20日

题目:Photonic topological metamaterials

报告人:杨镖 副教授 (国防科技大学)

时  间:2020年7月21日(周二)下午14:00-15:30

地  点:腾讯会议 ID:981 135 569 无密码

摘要:Topology, a mathematical concept associated with global perspectives, was found to represent geometric aspects of physics. To date, various topological phases have been proposed and classified. Among them, topological gapless phases focusing on the degeneracies of energy bands serving as the singularities in the momentum space, attract much attention. Especially in the three-dimension, various topological semimetals have been proposed. With unit topological charge ±1, Weyl degeneracies have laid the foundation. Also, they show loads of exotic properties, such as Fermi arcs and chiral anomalies. Being relied on the band topology theory, topological gapless phases have also been transferred into classic systems, such as photonics, acoustics and mechanics.

We experimentally investigated photonic Weyl systems in the photonic continuum media, where electromagnetic intrinsic degrees of freedom play key roles in constructing the state space. Firstly, I will talk about chiral hyperbolic metamaterials, a type-II Weyl metamaterials, from which we directly observed topological surface-state arcs. Then, I will present the discovery of ideal photonic Weyl systems, where helicoid structure of nontrivial surface states has been demonstrated. Finally, I will introduce photonic Dirac points, through analyzing eigen reflection field, we found the correlation of topological charges in momentum and real spaces. I will also talk about some very recent works in photonic topological metamaterial systems, including time-reversal breaking Weyl points in magnetized plasma and non-Abelian nodal links in bi-axial hyperbolic metamaterials.

简历:Biao YANG is now an associate professor in National University of Defense Technology. He currently also is a postdoc working with Prof. C. T. Chan in the Hong Kong University of Science and Technology. He got his Ph.D. from University of Birmingham (2018, Supervisor: Prof. Shuang Zhang) and bachelor’s degree from National University of Defense Technology (2011). Dr. Yang mainly works on photonic topological metamaterials, other research interests include topological K theory and index theory. As the first author, his publications include Science, PRL, Nature Communications, etc.

联系方式:cuicuilu@bit.edu.cn

邀请人:路翠翠 副研究员

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承办单位:物理学院、先进光电量子结构设计与测量教育部重点实验室

 
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