Chiroptical properties of patterned nanocrystal solids

手性材料和物体是我们生活的中心。生物分子和药物以特定的几何形状合成，以实现选择性和有针对性的相互作用，而螺旋和转子等物体将旋转运动转化为线性力。然而，具有纳米级或中尺度尺寸的手性材料的例子非常少。这些长度尺度的材料对于与偏振光的相互作用特别重要。手性分子对不同偏振态的光的吸收程度不同，在适当设计的纳米结构中，这种效应要强几个数量级。偏振光的检测是传感器和成像系统的组成部分，而圆偏振光的产生对于立体显示器、防伪安全和量子光学电路的发展至关重要。该项目的重点是纳米结构材料的设计，制造和表征的基本原理，通过创建由发光纳米晶体组成的新纳米结构来控制圆偏振光的吸收和发射。该项目还推进了纳米图案化和制造领域。进行的研究将培养学生在光子学，纳米技术和材料表征。作为该项目的一部分，PI将利用在线教育模式进行高级顶点课程，并在课堂上进行教育研究。PI还将让K-12学生参与先进的技术，并与当地的视觉艺术家合作。手性纳米结构和超颖表面与圆偏振光的相互作用比它们的分子对应物更强。然而，许多技术应用将受益于圆偏振光致发光的受控产生。该项目创建并表征了由等离子体纳米结构和半导体纳米晶体定制组件组成的超表面，其中纳米晶体使用直写电子束光刻法图案化为分层结构。实验的补充全场电磁模拟，以了解纳米晶体和等离子体纳米结构之间的相互作用。通过调整半导体纳米晶体的位置和形状，这些多材料超颖表面提供增强的角度控制和增强的圆偏振度。从这些研究中获得的理解有助于立体显示器，防伪策略和光子电路的发展。学生获得不同技术的经验，包括光刻合成，光刻图案，光学表征和电磁模拟。该项目还研究了本科课程的包容性和考试焦虑的作用，在高级顶点设计课程中培训本科生，让K-12学生参与与光偏振相关的活动，并与当地视觉艺术家合作开发艺术装置，让更广泛的社区体验光-该奖项反映了NSF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。

Chiral materials and objects are central to our lives. Biomolecules and pharmaceuticals are synthesized in specific geometries to enable selective and targeted interactions, while objects such as screws and rotors convert rotational motion to linear force. However, there are very few examples of chiral materials with nanoscale or mesoscale dimensions. Materials at these length scales are particularly important for interactions with polarized light. Chiral molecules absorb different polarization states of light to different extents, the effect is orders of magnitude stronger in appropriately designed nanostructures. The detection of polarized light is integral to sensors and imaging systems, and the generation of circularly polarized light is essential to the development of stereoscopic displays, of anti-counterfeiting security, and of quantum optical circuits. This project focuses on the fundamentals of the design, fabrication, and characterization of nanostructured materials to control the absorption and emission of circularly polarized light by creating new nanostructures comprised of light-emitting nanocrystals. The project also advances the fields of nanopatterning and fabrication. The research conducted will train students in photonics, nanotechnology, and materials characterization. As part of this project, the PI will leverage online education modalities for a senior capstone course and conduct educational studies in the classroom. The PI will also engage K-12 students with advanced technology and collaborate with a local visual artist.Chiral nanostructures and metasurfaces exhibit orders-of-magnitude stronger interactions with circularly polarized light than their molecular counterparts. Many technological applications, however, would benefit from the controlled generation of circularly polarized photoluminescence. This project creates and characterizes metasurfaces comprised of both plasmonic nanostructures and tailored assemblies of semiconductor nanocrystals, where the nanocrystals are patterned into hierarchical structures using direct-write electron beam lithography. The experiments are complemented by full-field electromagnetic simulations to understand the interactions between the nanocrystals and the plasmonic nanostructures. By tailoring the position and shape of the semiconductor nanocrystals, these multi-material metasurfaces offer both enhanced angular control and enhanced degrees of circular polarization. The understanding gained from these studies contributes to the development of stereoscopic displays, of anti-counterfeiting strategies, and of photonic circuits. Students gain experience in diverse techniques, including nanocrystal synthesis, lithographic patterning, optical characterization, and electromagnetic simulations. The project also studies inclusivity in undergraduate courses and the role of exam anxiety, trains undergraduate students in the senior capstone design course, engages K-12 students in activities related to light polarization, and develops art installations in collaboration with a local visual artist that allow the broader community to experience light-matter interactions at a larger scale.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.