Collaborative Research: Metasurface-Enabled Broadband Circular Dichroism Spectroscopy and Imaging

在化学系化学测量与成像项目的支持下，耶鲁大学的郭培军和他的团队以及宾夕法尼亚州立大学的倪兴杰和他的团队正在合作推进手性分子（即显示手性的分子）和材料的表征。圆二色性（CD）是一种可用于探测分子手性的光学性质。Guo/Ni团队正在设计超表面——一种可以操纵各种光性质的结构，包括其手性——以显着简化CD光谱仪，从而促进CD光谱和成像实验，具有显着的灵敏度和高通量。该项目为研究生和本科生提供纳米制造、光-物质相互作用以及先进光学测量装置的组装和适应等领域的实践培训。此外，该项目旨在通过与耶鲁大学路径和宾夕法尼亚州立大学科学拓展办公室合作，让K-12学生参与研究，激励年轻学生冒险进入STEM（科学、技术、工程和数学）领域。该合作项目的重点是设计、制造和评估用于圆二色性（CD）测量的新方法的元表面。超表面被设计为跨越从紫外线到太赫兹的波长范围，其中一部分目前还没有被商用CD光谱仪覆盖。几种典型的手性系统，包括手性分子、手性胶体纳米晶体和手性二维杂化钙钛矿，正被用于超表面光学工具的基准测试。超表面本质上是衍射的，因此它们可以实现单镜头兼容的CD表征，使它们在监测不可逆化学过程方面具有宝贵的价值。超表面可以结合在其他光学测量技术，如磁光克尔效应和时间分辨法拉第旋转。这些技术为理解化学合成和催化、能量转换和量子信息科学提供了强有力的探针。参与该项目的学生将获得对纳米光子学，光谱学和成像方法的深刻理解，为这些快速发展的科学领域提供有价值的，实用的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Peijun Guo and his group at Yale University and Xingjie Ni and his group at Pennsylvania State University are collaboratively advancing the characterization of chiral molecules (i.e. molecules that display handedness) and materials. Circular dichroism (CD) is an optical property that can be used to probe molecular chirality. The Guo/Ni team is engineering metasurfaces – structures that can manipulate various properties of light, including its chirality – to significantly simplify CD spectrometers, thereby facilitating CD spectroscopy and imaging experiments with remarkable sensitivity and high throughput. The project offers hands-on training to both graduate and undergraduate students in areas of nanofabrication, light-matter interactions, and the assembly and adaptation of advanced optical measurement setups. Moreover, the project aims to motivate younger students to venture into STEM (science, technology, engineering and mathematics) fields by partnering with the Yale Pathways and the Office of Science Outreach at Penn State to engage K-12 students to the research.This collaborative project focuses on the design, fabrication, and evaluation of metasurfaces for a novel approach to circular dichroism (CD) measurements. The metasurfaces are designed to span wavelengths ranging from the ultraviolet to terahertz, portions of which are presently not covered by commercial CD spectrometers. Several prototypical chiral systems, including chiral molecules, chiral colloidal nanocrystals, and chiral two-dimensional hybrid perovskites, are being used for benchmarking the metasurface-enabled optical tools. The metasurfaces are intrinsically diffractive, hence they enable single shot-compatible CD characterization, making them invaluable for monitoring irreversible chemical processes. The metasurfaces can be incorporated in other optical measurement techniques such as magneto-optic Kerr effect and time-resolved Faraday rotation. These techniques offer powerful probes for understanding chemical synthesis and catalysis, energy conversion, and quantum information science. Students involved in this project will acquire a profound understanding of nanophotonics, optical spectroscopy, and imaging methods, offering them valuable, practical insights into these rapidly evolving scientific fields.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.