报告题目：Chiral Optical Properties of Hybrid Nanostructures
报告人：张伟研究员 北京应用物理与计算数学研究所
报告时间：2021年05月13日上午10点
报告地点：物理科技楼101
报告人简介：张伟，北京应用物理与计算数学研究所，研究员。1998年于中科院理论物理研究所获博士学位，1998至2000年在北京应用物理与计算数学研究所做博士后，2001至2007年在美国Ohio Univ.、Univ. of Kentucky、Indiana Univ.做博士后/研究学者，2007年8月至今，研究员，北京应用物理与计算数学研究所。张伟在低维凝聚态/纳米体系的光学、电输运性质等方面做了系统的研究工作，在包括Nature、Phys. Rev. Lett.、Advanced Materials、 Angew. Chem. Int. Ed.、 Nano Lett.、 ACS Nano、J. Am. Chem. Soc.等的国际核心期刊上发表SCI论文/专著章节100余篇。2014年获“于敏数理科学奖”。
报告摘要：Modern nanotechnology opens the possibility of combining nanocrystals of various materials with very different characteristics in one superstructure, which possesses nontrivial (chiral) optical properties. In this talk, I will present our studies on the chiroptical properties of hybrid nanostructures composed of metallic nanoparticles, molecules , etc., focusing on the key mechanisms of chirality at the nanometer scale and strong coupling effect. The tunable hybrid nanostructures bring about strong chiral responses in certain designed structures. The interaction between molecules and metallic nanorods (NPs) leads to strong induced plasmonic circular dichroism (CD), which can be manipulated by the conformation of the nanoassemblies. The DNA-based assembly provides a remarkable spatial control of plasmonic nanostructures, which results in both the induced CD and structural CD. The strong coupling between plasmons and excitons leads to hybridized states-plexcitons and results in mode splitting and anticrossing behavior in both the circular dichroism (CD) and extinction spectra of the hybrid nanosystems. Moreover, we propose and justify a new criterion of strong plasmon−exciton interaction, depending only on the mode's position (without the explicit information on mode broadening). Our results not only deepen our understanding of the optical chirality at the nanometer scale, but also provide useful guidance for the design of sensors based on optical activity.
