CAREER: Exploring chiral edge plasmons in novel two-dimensional materials

非技术描述：在纳米尺度上控制光流动的能力对于实现用于快速数据处理和宽带信号通信的功能光学电路是极其重要的。然而，与电子信号不同的是，在纳米尺度上控制光学信号是具有挑战性的。这个项目探索了一类具有原子厚度的新型材料，其中一种具有纳米级足迹的特殊类型的光可以在这些材料的边缘传播。此外，还主动控制了纳米级光的方向和强度，在一定条件下只允许单向传输。这项研究的主要目的是揭示这些纳米级光的一般特征和关键功能，为其在下一代计算机中的应用铺平道路。该项目为指导和培训高中生、本科生和研究生，特别是那些在科学和工程领域没有代表性的少数群体的学生提供了机会。此外，该项目团队还为公众提供二维材料或光学主题的特殊外展活动，并为爱荷华州立大学的高级实验室课程设计新的教材。技术描述：该项目团队旨在通过探索新型二维材料中的手性边缘等离子体来实现对纳米热子信号的最终控制。这些边缘模是由原子薄样品中的光子和电子之间的耦合形成的，可以严格地沿着样品的边缘传播。手性是通过施加磁场或在光激发下诱导净Bloch带Berry曲率来引入的。最先进的散射型扫描近场光学显微镜将在低温和强磁场下提供超快、超小型和宽带的手征边缘等离子体成像和光谱。利用这项技术，项目组计划对基准二维材料--石墨烯和六族过渡金属二卤化物--中的手性等离子激元进行系统研究。主要目标包括表征手性等离子激元的一般性质，并展示这些模式与纳米尺度信号控制相关的基本功能。这项研究有望加深我们对与二维材料中电子-电子相互作用和Berry曲率相关的耐人寻味的纳米光学物理的理解，彻底改变我们在技术上具有重要意义的太赫兹到红外区域的可调谐手性等离子激元的方法，并建立手征边缘等离子激元作为具有宽带和主动可调谐的非互易信号通信的新介质。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Description: The capability of controlling the flow of light in the nanoscale is extremely important for realizing functioning optical circuitry for fast data processing and broadband signal communications. Nevertheless, unlike electronic signals, it is challenging to control optical signals in the nanoscale. This project explores a class of novel materials with atomic thicknesses, where a special type of light with nanoscale footprints can travel at the edges of these materials. Moreover, both the direction and the intensity of the “nanoscale light” are actively controlled, and only one-way transport is allowed under certain conditions. The main goal of this research is to uncover the general characteristics and key functionalities of these “nanoscale light”, which could pave the way for its applications in next-generation computers. This project provides opportunities for mentoring and training high-school, undergraduate and graduate students, especially those from unrepresentative minorities in science and engineering. In addition, the project team offers special outreaching activities in the themes of two-dimensional materials or optics for the public and designs new teaching materials for advanced lab courses at Iowa State University.Technical Description: The project team aims to realize the ultimate control of nanophotonic signals by exploring chiral edge plasmons in novel two-dimensional materials. These edge modes are formed by the coupling between photons and electrons in the atomically-thin samples and can propagate strictly along the sample edges. The chirality is introduced either by applying a magnetic field or inducing net Bloch band Berry curvature with optical excitations. State-of-the-art scattering-type scanning near-field optical microscopy will provide ultrafast, ultrasmall and broadband imaging and spectroscopy of chiral edge plasmons at cryogenic temperatures and high magnetic field. With this technique, the project team plans to perform systematic studies of chiral plasmons in the benchmark two-dimensional materials – graphene and group six transition-metal dichalcogenides. The main objectives include characterizing the general properties of chiral plasmons and demonstrating the basic functionalities of these modes related to nanoscale signal control. The research is expected to deepen our understanding of the intriguing nano-optical physics in association with electron-electron interactions and Berry curvature in two-dimensional materials, revolutionize our approach towards tunable chiral plasmonics in the technologically important terahertz to infrared regions, and establish chiral edge plasmons as novel media for nonreciprocal signal communications with broad bandwidth and active tunability.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.