报告题目：Symmetry in light scattering and finite element optical solver development

报告人：陈云天(华中科技大学)

报告时间：2021年12月4日（周六）下午2:30

报告地点：物理学院新楼五楼多功能厅

报告摘要：Symmetry is an indispensable tool to study different branches in physics, which also applies in optics and light scattering. In this work, we systematically introduce the concept of symmetry operation, and group approaches to examine the light scattering for finite scatters. Firstly, we reveal constraints of electromagnetic multipoles for symmetric scatterers, and scattering invariances of far-field patterns for arbitrary particle clusters based on duality symmetry and combined duality- rotation symmetry (n-fold, n≥3). Secondly, for finite scatters or scatter cluster with rotation symmetry (n-fold, n≥3), we prove that the invariant extinctions for arbitrary polarizations on the same latitude circle of the Poincare sphere and combined extra symmetry ensures invariant extinction, scattering and absorption for all polarizations covering the whole Poincare sphere. Thirdly, we examine the chiral responses of open photonic structures from perspectives of quasi-normal modes and polarization singularities of their far-field radiations. As plane waves are incident along those directions of mode singularity, the reciprocity ensures ideal maximization and minimization of optical chiralities, for corresponding mode radiations of circular and linear polarizations respectively. Lastly, I will briefly report our recent progress in the development of finite element optical solver.

报告人简介：陈云天，华中科技大学光电学院、武汉国家光电研究中心副教授，博士生导师，在纳米光子学及电磁学计算等相关领域发表包括Nature Comm, PRL, Light, PNAS等主流期刊50多篇，承担基金委等国家级项目多项。研究方向包括复杂介质中光传输和散射现象，光学数值计算方法，及光电器件的理论建模、仿真与设计优化及软件开发。

邀请人：张顺平教授