Manipulating Light at the Subwavelength Scale and Related Applications
亚波长光场调控与应用
Yuanmu Yang（杨原牧）
ABSRACT
Optical science and technology have undergone remarkable development over the past few centuries, with some major impact on our daily life. Our knowledge about light has also evolved over time. The design of microscope and telescope, with a characteristic length of the instrument much greater than the wavelength of light, were mainly based on the ray-tracing principle in geometric optics. Following the later development of wave optics, new optical elements such as gratings and spatial light modulators with characteristic length scale on the same order of the wavelength of light are invented. Moving into the 21st century, following the rapid advancement of nanofabrication techniques and numerical simulation tools, manipulating light at the sub-wavelength scale becomes possible, which leads to the development of new concepts such as metamaterials and metasurfaces. Recently, by leveraging innovation in physics and materials science, we try to realize a series of novel subwavelength optical elements. In this talk, I will introduce our recent work on:
1)How to leverage subwavelength-thick optical thin film with an epsilon-near-zero response to overcome limitations of conventional nonlinear optical crystal, to realize nonlinear light sources emitting in the UV and THz spectral range;
2)How to combine optical metasurfaces with conventional light sources or detectors, to build miniatured optical sensors that may detect multi-dimensional light information such as depth and polarization of a scene.
光科学与技术在过去几百年间历经了长足的发展，在很多方便影响着人们的生活。人们对光的认知也在不断地在深入。最初人们发明显微镜、望远镜等特征尺寸远大于光波长的光学仪器，依据的是几何光学中的光线追迹原理。随着后来波动光学理论的发展，人们进而实现了特征尺寸在光波长量级的光栅、空间光调制器等新型光学元件。进入21世纪，伴随着纳米加工技术和光学数值仿真工具的快速发展，人们逐渐开始获得了在亚波长尺度灵活调控光场的能力，发展出了超构材料、超构表面等新概念。近年来，我们力图通过物理、材料的创新，实现一系列新型亚波长光学元件。本次报告中，我将具体介绍：
1）如何利用亚波长厚度的、具有介电常数近零特性的光学薄膜，突破传统非线性光学晶体的限制，实现新型的紫外和太赫兹波段光源；
2）如何通过由亚波长尺寸光学天线构造的超构表面与传统光源或探测器结合，构造微型、低成本的高性能新型光学传感器，实现对深度、偏振等多维光场信息的感知。
BIOGRAPHY
Yuanmu Yang has been a tenure-track associate professor at the Department of Precision Instrument at Tsinghua University since 2018. His main research interest is in meta-optics. By engineering and enhancing light-matter interaction at the subwavelength scale, he aims to overcome the limitation in size and functionality of conventional diffractive optical elements and nonlinear optical crystals, and realize novel subwavelength optical elements. His research currently focuses on subwavelength optical thin-films and metasurfaces for applications in nonlinear optics and multi-dimensional light field sensing. Before joining Tsinghua, he obtained his bachelor’s degree in optoelectronics from Tianjin University/Nankai University in 2011, and his PhD in interdisciplinary materials science from Vanderbilt University in 2015. He was a postdoctoral researcher at Sandia National Laboratories from 2015 to 2017, and was a research scientist at Intellectual Ventures from 2017 to 2018, in an attempt to commercialize the optical metasurface technology. His work has been published in high impact journals such as Nature Photonics and Nature Physics, receiving over 3000 citations. His recognitions include the outstanding oversea student award given by the Chinese Scholarship Council as well as the Forbes China “30 under 30” in 2018.
杨原牧自2018年起任清华大学精密仪器系准聘副教授。主要研究兴趣为超构光学，力图通过在亚波长尺度灵活调控并增强光与物质的相互作用，突破传统衍射光学元件和非线性光学晶体在集成度、功能性等方面的局限，实现一系列新型亚波长光学元件。近期的研究重点是亚波长光学薄膜和超构表面在非线性光学以及多维光场感知中的应用。在加入清华大学之前，他于2011年获天津大学/南开大学光电子技术与科学专业学士学位，2015年获美国范德堡大学交叉材料科学博士学位，2015-2017年在美国Sandia国家实验室从事博士后研究，2017-2018年在美国Intellectual Ventures公司工作，从事光学超构表面的产业化研发。多次在Nature Photonics、Nature Physics等高影响力期刊发表研究论文，文章总引用3000余次。获得的奖项与荣誉包括国家留学基金委优秀留学生奖学金、福布斯中国2018年度“30位30岁以下优秀科学家“等。