CAREER: Light Manipulation in Metal-Dielectric Multilayer Metamaterials with Large Anisotropy

非技术描述：超材料是一种人工构造的复合材料，其性能与天然材料有很大不同。光学材料的介电常数是衡量其储存电磁能和将电磁能转化为热能能力的重要指标。最常见的光学材料的介电常数通常是各向同性的(即，在所有方向上都是相同的)，对于介电或透明材料，如玻璃和水，介电常数为正值。通过将介质和金属薄层按顺序排列，新型光学超材料，即金属-介质多层超材料，被创造出具有自然材料无法实现的介电常数：其介电常数被设计为非常大或非常小，并且在材料的不同方向上是不同的。在这项研究中，多层超材料被用来研究光传播和操纵的新现象，并解决当前光学超材料面临的挑战。这项研究为多层超材料在光通信、成像处理、传感、太阳能收集和自适应光学中的应用奠定了基础。这项研究工作与教育和推广活动相结合，包括培训学生学习超材料，在本科和研究生课程中开发光学学习模块，并为包括K-12学生在内的公众组织纳米技术研讨会。技术描述：这个职业奖项的研究部分的目标是研究使用具有大的各向异性的金属-介电多层超材料的非凡光操纵，包括epsilon-近零、双曲线和epsilon非常大的超材料，并使用这些超材料探索新的光学物理现象。本研究采用理论分析、数值模拟、材料制备和实验表征相结合的方法，对多层超材料中的光-物质相互作用有了基本的了解。这项研究包括以下部分：(I)通过探测超材料在幅度和相位上的反射和透射率，精确确定超材料的有效介电常数；(Ii)通过Zitterbewegung和Klein隧道效应探索周期和准周期多层超材料中的光学非定域性，以实现Dirac物理；(Iii)设计图案化多层双曲线超材料，用于产生复杂的光矢量涡旋光束，以探索结构光操纵；以及(Iv)验证损耗各向异性超材料的新概念，以演示吸收损失诱导的传输和光束传输的反直观现象。

Nontechnical Description: Metamaterials are artificially structured composite materials with properties significantly different from those of the natural materials. The permittivity of an optical material is an important measure of its ability to store electromagnetic energy and to convert electromagnetic energy into heat. The permittivities of the most common optical materials are usually isotropic (i.e., the same value in all directions), with positive values for dielectric or transparent materials such as glass and water. By placing dielectric and metallic thin layers in alternative order, new types of optical metamaterials, namely metal-dielectric multilayer metamaterials, are created with permittivities that could not be realized using natural materials: with permittivity values designed to be very large, or very small, and different in different directions of the materials. In this research multilayer metamaterials are utilized to study novel phenomena of light propagation and manipulation and to address current challenges in optical metamaterials. This research paves the way for advances of multilayer metamaterial-based applications in optical communications, imaging processing, sensing, solar energy harvesting and adaptive optics. The research effort is integrated with education and outreach activities, including training students in metamaterials, development of optics learning modules in undergraduate and graduate courses, and organizing a nanotechnology workshop for public audiences, including K-12 students.Technical Description: The goals of the research component of this CAREER award are to study extraordinary light manipulation using metal-dielectric multilayer metamaterials with large anisotropy, including epsilon-near-zero, hyperbolic, and epsilon-very-large metamaterials, and to explore new optical physics phenomena using these metamaterials. Combined approaches of theoretical analysis, numerical simulation, materials fabrication and experimental characterization are used in the research to gain fundamental understanding of light-matter interactions in multilayer metamaterials. The research includes the following components: (i) accurate determination of the effective permittivity of metamaterials by probing the reflectance and transmittance, in both amplitude and phase, via an advanced optical vortex spectroscopic technique; (ii) exploring optical nonlocalities in periodic and quasiperiodic multilayer metamaterials for realization of Dirac physics via Zitterbewegung and Klein tunneling effects; (iii) design of patterned multilayer hyperbolic metamaterials for the generation of complex optical vector vortex beams to explore structured light manipulation; and (iv) verification of a novel concept of loss-anisotropic metamaterials, to demonstrate counterintuitive phenomena of absorption loss induced transmission and beam propagation.