Polaritonics Platform for Terahertz Signal Processing, MultipleScattering, and Field Enhancement

目的：本项目的目标是研究：(I)太赫兹信号在传感和成像中的应用，以及(Ii)太赫兹光谱学的场强增强。在主题(I)中，将使用太赫兹极化电子平台测试多个电磁波散射模型。飞秒激光加工将被用于钻孔，并将不同尺寸和空间分布特性的特定结构雕刻成Nb酸锂晶体薄膜。太赫兹波将在薄膜中产生并被检测到。这一结果将指导太赫兹成像方法的发展。在主题(Ii)中，将开发用于提供太赫兹场增强的掺杂半导体腔和光波导。磁场可能足以驱动高度非线性的材料响应，包括结构相变和介电击穿。这将允许直接的时间分辨光学观测以及对复杂材料转变的广泛控制。智能优点相对于微波和光学，太赫兹光谱一直没有得到充分利用，这在很大程度上是因为缺乏源和探测器。这些领域的最新进展为控制太赫兹信号、成像和光谱学的新方法提供了机会，这些主题将被讨论。更广泛的影响两名博士生将获得该奖项的支持。在麻省理工学院，该项目将与纳尔逊团队运营的大学前外展计划的扩展计划相吻合。在普渡大学，本科生将被招募到韦伯小组中从事这一项目。

Objective The objectives if this project are to investigate: (i) Multiply-scattered terahertz signals in sensing and imaging applications, and (ii) Terahertz field enhancement for spectroscopy. In Topic (i), models of multiple electromagnetic wave scattering will be tested using a terahertz polaritonics platform. Femtosecond laser machining will be used to drill holes and carve specified structures with different dimensions and spatial distribution properties into lithium niobate crystalline films. Terahertz waves will be generated and detected in the films. The results will guide the development of methods for terahertz imaging. In Topic (ii), doped semiconductor cavities and waveguides will be developed to provide terahertz field enhancement. The fields may be sufficient to drive highly nonlinear material responses including structural phase transitions and dielectric breakdown. This will permit direct time-resolved optical observation as well as extensive control over complex material transformations.Intellectual MeritThe terahertz spectrum has been underutilized, relative to microwaves and optics, in large part because of a dearth of sources and detectors. Recent progress in these areas presents opportunities for new methods for controlling terahertz signals, for imaging, and for spectroscopy, and these topics will be addressed. Broader ImpactTwo Ph.D. students will be supported by this award. At MIT, the project will dovetail with a planned expansion of a pre-college outreach program run by the Nelson group. At Purdue, undergraduate students will be recruited to work on this project in the Webb group.