Low-Loss, Impedance-Matched Dirac-Cone Metamaterials for Integrated Optics

非技术描述：该项目实现了一种新形式的光学材料--零折射率集成阻抗匹配超材料。这些材料不会像普通透明材料那样弯曲光线，可以集成到光学设备中。利用这个新的材料平台，这个项目探索了零折射率材料的奇异物理，并在集成光子学中实现了许多应用，包括光束操纵和超耦合。为了有效地将这种新型光学超材料从学术界转移到商业应用，研究团队与业界合作伙伴密切合作。这个项目在两个方面为首席研究人员在教育和推广方面的工作做出了贡献：第一，这种新型的超材料可以作为一个简单的平台，在教育和展览中展示超材料的奇异材料属性和有趣的物理现象；第二，参与这个项目的许多不同层次的学生获得了最先进的研究经验。技术描述：这个项目研究的是位于光子晶体布里渊区中心的狄拉克锥体实现的光学超材料。由于光子晶体在伽马点附近满足均匀化准则，因此可以将光子晶体视为在狄拉克点附近具有低折射率或零折射率的均匀的块体超材料。这种方法有三个重要的优点：低损耗、自由空间阻抗匹配和各向同性。这个项目的目标是设计、制造和表征由二维正方形硅柱阵列组成的狄拉克锥形超材料，这种超材料可以用标准的平面工艺制造，然后基于这个二维平台，从理论和实验上展示几种奇异的物理现象和潜在的应用，包括波束控制和超耦合。具体地说，研究方法是：1)使用分析模型和商用模拟器进行理论设计；2)使用哈佛纳米系统中心的净室设施进行实验制造；3)使用光纤发射耦合系统对狄拉克锥形超材料的光学性质进行实验测量。

Non-technical Description: This project implements a new form of optical materials - integrated impedance-matched metamaterials with zero refractive index. These materials do not bend light like ordinary transparent materials and can be incorporated in optical devices. Using this novel material platform, this project explores the exotic physics of zero refractive index materials and implements a number of applications in integrated photonics, including beam-steering and super-coupling. To efficiently transfer this new type of optical metamaterial from academia to commercial applications, the research team collaborates closely with industrial partners. This project contributes to the Principal Investigators' effort in education and outreach in two ways: first, this novel type of metamaterial can be used as a simple platform in education and exhibitions to demonstrate the exotic material properties and interesting physical phenomena of metamaterials; second, students at many different levels involved in this project gain research experience in state-of-the-art research.Technical Description: This project investigates optical metamaterials achieved by a Dirac cone at the center of the Brillouin zone of a photonic crystal. Because the homogenization criterion is met in the vicinity of the Gamma point, the photonic crystal can be treated as a homogeneous bulk metamaterial with low or zero refractive indices near the Dirac point. This approach offers three important advantages: low loss, free-space impedance matching, and isotropy. The goal of this project is to design, fabricate, and characterize Dirac-cone metamaterials consisting of 2D square array of silicon pillars, which can be fabricated using standard planar processes, then, based on this 2D platform, to theoretically and experimentally demonstrate several exotic physical phenomena and potential applications including beam-steering and super-coupling. Specifically, the research approaches are: 1) theoretical design using analytical models and commercially available simulators; 2) experimental fabrication using the clean room facilities at the Harvard Center for Nanoscale Systems; 3) experimental measurements of optical properties of Dirac-cone metamaterials using a fiber-launch coupling system.