Developing anisotropic media for transformation optics by using dielectric photonic crystals

职务名称：非技术描述：变换光学（TO）是基于坐标变换，这需要适当的介质参数的空间色散。这样的介质迫使在原始坐标系中移动的电磁（EM）波表现得好像它们在变换的坐标系中传播一样。因此，TO为设计具有上级功能的先进EM设备引入了一种新的强大技术。坐标变换可以用于压缩，扩展，弯曲或扭曲空间，使隐形斗篷，场集中器，完美透镜，光束移位器等的设计成为可能，可能会给人类生活的各个领域带来进步。这些装置的实现取决于产生具有规定EM特性的介质的可能性，特别是定向折射率，以提供具有超光速相速度的波传播和在法线方向上的高折射率，以引起波沿沿着曲线路径运动。 最初，由微小的金属谐振器组成的人造超材料（metamaterials，简称metamaterials）被选择用于构建转换介质。然而，遇到了一些严重的挑战，例如极窄的工作频带和金属元件的高损耗。所提出的方法是使用介电光子晶体来克服MM介质的这些主要限制。该项目将使研究生和本科生，特别是工程专业的妇女，参与理论和实验EM研究。拓展活动包括为K-12学生举办的几个青年项目中的讲座和实践项目。技术描述：该项目将开发一个基于光子晶体（PhC）的媒体工程平台，该平台不受超材料媒体的主要限制。该项目旨在控制波在介质中沿沿着正交结晶方向的传播，并依赖于自准直现象，制定基于TO的折射率处方。为了实现超光速和普通折射率沿晶体所需轴沿着的定向色散，将使用它们的晶格参数的适当变化。通过从具有优化尺寸的晶体碎片构建介质，将提供折射率值的精确控制。微波实验使用平行板波导室将进行记录波的传播和验证计算结果。 早期开发的低损耗光子晶体管制造技术将有助于实现实际器件。这种跨学科的研究将整合电磁学，物理学，光学和材料科学的概念;采用全波计算建模和设计;工程复杂的材料架构;并掌握复杂结构的表征技术。该项目将通过开发媒体工程的新方法和解决基本问题，包括自准直的集成，为TO开辟前景。这项研究将整合电磁学，物理学，光学和材料科学的概念，并将推进PhCs的潜力。

Title: Novel media for transformation optics using dielectric photonic crystalsNon-Technical Description: Transformation optics (TO) is based on coordinate transformations, which require proper spatial dispersions of the media parameters. Such media force electromagnetic (EM) waves, moving in the original coordinate system, to behave as if they propagate in a transformed coordinate system. Thus TO introduces a new powerful technique for designing advanced EM devices with superior functionalities. Coordinate transformations can be derived for compressing, expanding, bending, or twisting space, enabling designs of invisibility cloaks, field concentrators, perfect lenses, beam shifters, etc., that may bring advances to various areas of human life. Realization of these devices depends on the possibility of creating media with prescribed EM properties, in particular, directional refractive indices to provide wave propagation with superluminal phase velocities and high refractive indices in the normal direction to cause wave movement along curvilinear paths. Originally, artificial metamaterials (MMs) composed of tiny metallic resonators were chosen for building transformation media. However, a number of serious challenges were encountered, such as extremely narrow frequency band of operation and the high losses in metal elements. The proposed approach is to use dielectric photonic crystals to overcome these major limitations of MM media. This project will allow graduate and undergraduate students, especially women in engineering, to participate in theoretical and experimental EM research. Outreach activities include lectures and hands-on projects in several youth programs to K-12 students.Technical Description: This project will develop a platform for engineering photonic crystal (PhC)-based media that are free from the major limitations of metamaterial media. The project aims to control wave propagation in media along orthogonal crystallographic directions and relies upon self-collimation phenomena at formulating TO-based prescriptions for refractive indices. For realizing directional dispersions of both superluminal and ordinary indices along desired axes of crystals, proper variations of their lattice parameters will be used. Accurate control of index values will be provided by building the media from crystal fragments with optimized dimensions. Microwave experiments using a parallel-plate waveguide chamber will be performed to record wave propagation and to verify computational results. Technologies developed earlier for fabricating low-loss PhCs will help to implement the practical devices. This interdisciplinary research will integrate electromagnetics, physics, optics, and materials science concepts; employ full-wave computational modeling and design; engineer complex materials architectures; and master characterization techniques for complex structures. The project will open up perspectives for TO by developing new approaches for media engineering and by solving fundamental problems, including integration of self-collimation. This research will integrate electromagnetics, physics, optics, and materials science concepts and will advance the potential of PhCs.