Enhancing helicity-dependent optical interactions in inversion-asymmetric materials

非技术描述：人类的眼睛已经进化到能够感知光的强度和颜色。然而，偏振为信息提供了一个额外的数据丰富的渠道——这一特性在螳螂虾和圣甲虫身上得到了很好的体现，这些物种都能看到圆偏振光。许多反转不对称材料——包括手性分子和原子薄材料——也优先“看到”（即吸收）左或右圆偏振光，但只是微弱的；事实上，左右圆偏振光的微分吸收比这些材料对非偏振光的吸收少了近5个数量级。本项目通过设计、合成和表征控制光-物质相互作用的新材料和纳米结构，增强分子和单层材料中圆偏振光的吸收和发射。通过增加手性光物质相互作用，该研究提高了药物的功效，减少了药物的不良副作用；减少除草剂和杀虫剂的毒性和对环境的影响；促进了高效的量子光电信息处理。作为项目的一部分，首席研究员正在与K-12学生和教师进行外展和指导，特别关注代表性不足的群体；开发新的本科和研究生课程；并通过剧作家的驻留来实现国家戏剧的生产。技术描述：许多反转不对称材料，包括手性分子和某些范德华材料，表现出对左右圆偏振光的微分吸收，比它们对非偏振光的吸收少了近五个数量级。这种微弱的差分吸收阻碍了单分子圆二色光谱、全光手性分辨率和量子信息的高效谷电子数据编码等应用。本项目的重点是增强分子和单层材料中依赖于螺旋度的光吸收、发射和载流子弛豫。该方法基于被称为超表面的纳米结构材料，当将其放置在分子或单层样品的近场中时，可以精确控制光的振幅，相位和偏振。利用全场电磁模拟设计强手性光吸收和发射的超表面。与此同时，高质量的因子介电超表面被制造出来，并开发了一套光学和原子力显微镜来表征超表面如何增强分子和单层的圆二色性、光致发光和对映选择性吸收。最后，利用这些超表面来控制分子和范德瓦尔斯材料中电子自旋取向和载流子动力学。该项目得出的结论有望应用于全光对映选择性传感与分离以及量子光信息的生成、传输和存储。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。

Nontechnical description: The human eye has evolved to perceive the intensity and color of light. However, polarization provides an additional data-rich channel for information - a property is beautifully embodied by mantis shrimp and scarab beetles, species which see circularly polarized light. Many inversion asymmetric materials - including chiral molecules and atomically-thin materials - also preferentially 'see' (that is, absorb) left- or-right circularly polarized light, but only weakly; in fact, the differential absorption of left and right circularly polarized light is nearly five orders of magnitude less than these materials' absorption of unpolarized light. This project enhances the optical absorption and emission of circularly-polarized light in molecular and monolayer materials through the design, synthesis, and characterization of new materials and nanostructures that control light-matter interactions. By increasing chiral light-matter interactions, the research increases the efficacy and reduces the unwanted side effects of pharmaceutical drugs; reduces the toxicity and environmental impact of herbicides and pesticides; and facilitates efficient quantum optoelectronic information processing. As part of the project, the Principal Investigator is engaging in outreach and mentoring with K-12 students and teachers, giving particular attention to underrepresented groups; developing new undergraduate and graduate curriculum; and implementing a national theatre production via a playwright residency.Technical description: Many inversion-asymmetric materials, including chiral molecules and certain van der Waals materials, exhibit a differential absorption of left and right circularly polarized light that is nearly five orders of magnitude less than their absorption of unpolarized light. Such weak differential absorption prohibits applications including single molecule circular dichroism spectroscopy, all-optical chiral resolution, and efficient valleytronic data encoding for quantum information. This project focuses on enhancing helicity-dependent optical absorption, emission, and carrier relaxation in molecules and monolayered materials. The approach is based on nanostructured materials known as metasurfaces, which, when placed in the near-field of a molecular or monolayer sample, precisely control the amplitude, phase, and polarization of light. Full-field electromagnetic simulations are used to design metasurfaces for strong chiral-optical absorption and emission. In parallel, high-quality factor dielectric metasurfaces are fabricated and a suite of optical and atomic force microscopies are developed to characterize how the metasurfaces enhance molecular and monolayer circular dichroism, photoluminescence, and enantioselective absorption. Finally, the metasurfaces are used to manipulate electron spin orientation and carrier dynamics in molecular and van der Waals materials with broken inversion symmetry. Conclusions drawn from the project are expected to find applicability in all-optical enantioselective sensing and separation as well as quantum optical information generation, transmission and storage.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.