时 间：2018年9月18日10:00-11:30
地 点：武汉光电国家研究中心A101
报 告 人：董建文 教授，中山大学物理学院
邀 请 人：黄振立 教授
报告人简介 (Biography)：
董建文，中山大学物理学院，教授，教育部青年长江学者，国家优青。曾在美国加州大学伯克利分校、香港科技大学做访问学者。长期从事光在人工非均匀材料中调控及其在光信息系统中的应用研究，研究领域涵盖纳米光子学，拓扑/能谷光子学，超构表面、光学全息等。较早开展时间反演不变光学系统的抗散射传输行为，国际上较早从拓扑光子学原理、到超构材料制备、到微纳光子器件等研究。发表了60余篇学术期刊论文，包含Nat. Mater., Nat. Commun., Phys. Rev. Lett., Adv. Mater.等。两篇ESI论文，其中一篇被选为“2017中国光学十大进展-基础研究”。
Dr. Jian-Wen DONG, Professor in School of Physics, Sun Yat-sen University (SYSU), Cheung Kong Scholar Youth Professor, NSFC Outstanding Youth Scientist. He was a visiting scholar in University of California, Berkeley (UCB) and Hong Kong University of Science and Technology (HKUST). His current research areas are nanophotonics, topological/valley photonics, metasurface and holography. He was interested in backscattering-immune propagation in time-reversal invariant system. He has systematically studied and known-how on the connections among topological photonics, metamaterial fabrication, and micro-nano devices. He has published over 60 research papers in scientific journals including Nat. Mater., Nat. Commun., Phys. Rev. Lett., Adv. Mater., etc. He has two ESI papers, one of which was selected as the "top ten progress of Chinese optics in 2017 - basic research”.
报告摘要 (Abstract)：
基于绝缘硅片（SOI）的纳米光子器件可以通过替换部分电子元件来改善现代信息处理系统性能。拓扑光子晶体的发现为控制光流提供了新的自由度，使实现新的光电功能和器件成为可能。基于SOI片的亚波长方案仍面临挑战，而能谷光子晶体（VPC）为此提供了一条可行道路。我们利用能谷自旋耦合效应，提出了非零能谷陈数的全介质能谷光子晶体，并且分别在微波波段和通讯波段成功实现。实验观察到宽带平顶高透射，证明了拓扑抗散射传输。上述工作将有利于微纳集成光子学和拓扑纳米光子学的发展。
本报告第二部分将介绍一种光学成像的新途径——氮化硅超透镜。我们制备了数值孔径为0.78、直径为1厘米的大口径氮化硅超透镜（由超过5亿根亚波长纳米柱子组成），实验上展示了良好的广角成像效果。结果有望用于光学成像透镜的微型化和平面化，在光纤成像、智能手机、全天空望远镜、近眼成像等领域具有较好的潜在应用价值。
Nanophotonic devices in silicon-on-insulator (SOI) platform can potentially improve the capabilities of modern information-processing systems by replacing some of their electrical counterparts. The discovery of topological photonics provides a new degree of freedom to control the flow of light, enabling novel optoelectronic functionalities and devices. However, the subwavelength strategy in SOI platform remains challenge. Valley photonic crystals (VPCs) pave an alternative way to achieve SOI topological nanophotonic devices with high performance. We have proposed all-dielectric VPCs with nonzero valley Chern number by employing spin-valley coupling, and achieved at microwave and telecommunication regions. Measurement results show flat-top high-transmittance spectra, verifying broadband back-scattering immune propagation. These works show a prototype of on-chip photonic devices, with promising applications for integrate photonics, and photonic analog of quantum information processing based on topological nanophotonic modes.
The second part of this talk is about a new way of imaging -- silicon nitride based metalens. Here, we experimentally realize the visible SiN divergent metalenses with NA~0.78. The metalens has 1-cm large diameter and over half billion nanopillars, which is achieved by using the mature CMOS-compatible fabrication process and keeps high-quality wide-angle imaging. Our findings may open a new door for the miniaturization of optical lenses in the fields of optical fibers, microendoscopes, and smart phones, as well as the applications in all-sky telescopes, large-angle beam shaping, and near-eye imaging.
