Broadband and tunable enhanced chiral light-matter interactions at the visible with new ultrathin helical metamaterials

非技术性描述：该项目推进了对光线如何通过由非常小的三维物体的配置创建的边缘和角落的理解。光路可以通过弹簧状纳米物体的尺寸和几何形状来操纵和控制，从而产生具有独特特性和功能的人工工程材料。该研究小组利用实验和计算方法来预测，制造和测试新的可编程光学纳米结构，这些纳米结构将被安排在预计支持下一代光通信和传感技术的配置中。因此，这项研究通过使用纳米结构的特定几何排列来缩小光操纵的差距。因此，该研究有利于美国的经济和社会。该项目支持本科生和研究生参与研究，作为鼓励在新光学材料方面追求高级学习和研究事业的一种手段。研究团队扩展了这项研究的影响，将与当前项目相关的先进光学概念引入STEM管道中代表性不足的人口群体，包括向内布拉斯加大学林肯分校物理科学本科女性会议（WoPhys）活动以及内布拉斯加州材料和纳米科学中心本科生项目的年度推广和研究经验。此外，研究人员利用他们的研究成果制作了一个视频，向更广泛的公众讲授光的性质，当前推进光学材料的研究活动，以及面向高性能量子光学和光子应用的未来器件技术。技术描述：纳米纤维技术的最新进展使光学纳米超材料的发展能够增强电磁手性。然而，目前表现出手性光-物质相互作用的纳米光子超材料设计具有极弱和窄带的性质，难以控制和增强，通常在红外频率下工作，并且不能被调谐。在这个项目中，研究小组通过设计新的介电紧凑亚波长螺旋超材料来解决这些问题，以在破纪录的水平和整个可见光谱下强烈增强和调整其手光响应。所提出的新的人工工程介电纳米材料有望为有效和相干地操纵宽带手性、光子的自旋角动量和入射电磁波的横向光子自旋开辟新的途径。新的方法预计将导致方向性的自旋极化辐射和未扰动的手征边缘模式沿着界面具有不同的手性。本文从理论和实验两方面研究了低损耗全介质螺旋形超材料，并将其应用于不同的令人兴奋的新应用，如新的手性波导和纳米腔的设计。介电纳米螺旋的结构诱导的强手旋光响应通过改变它们的几何形状被调谐到可见光的不同频率。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。

Nontechnical description: This project advances understanding about how light passes around edges and corners which are created by configurations of very small three-dimensional objects. The light path can be manipulated and controlled by the size and geometry of spring-like nanoobjects, leading to artificially engineered materials with unique properties and functionalities. The research team utilizes experimental and computational approaches to predict, manufacture and test new ultrathin optical nanostructures which will be arranged in configurations that are expected to support next generation optical communications and sensing technologies. Thereby the study closes a gap in the manipulation of light by using specific geometrical arrangements of nanostructures. By that, the research benefits the economy and society of the United States. The project supports undergraduate and graduate student involvement in research as a means of encouraging pursuit of advanced study and research careers in new optical materials. The research team extends the impact of this research to introduce advanced optical concepts relevant to the current project to underrepresented demographic groups in the STEM pipeline, including presentations to the Conference for Undergraduate Women in Physical Sciences (WoPhys) events at the University of Nebraska-Lincoln and the annual outreach and Research Experiences for Undergraduates programs of the Nebraska Center for Materials and Nanoscience. Further, the investigators leverage their research findings to create one video to teach the broader public about the properties of light, current research activities for advancing optical materials, and future device technologies towards high-performance quantum optical and photonic applications.Technical description: Recent advances in nanofabrication techniques have enabled the development of optical nanoscale metamaterials to enhance electromagnetic chirality. However, current nanophotonic metamaterial designs that exhibit chiral light-matter interactions have an extremely weak and narrowband nature, are difficult to control and enhance, usually operate at infrared frequencies, and cannot be made tunable. In this project, the research team tackles these problems by designing new dielectric compact subwavelength helical metamaterials to strongly enhance and tune their chiroptical response at record-breaking levels and at the entire visible spectrum. The proposed new artificially engineered dielectric nanomaterials are expected to unlock novel ways for the efficient and coherent manipulation of the broadband chirality, spin angular momentum of photons, and transverse photon spin of incident electromagnetic waves. The new approach is anticipated to lead to directional spin-polarized radiation and unperturbed chiral edge modes along interfaces with different handedness. Low-loss all-dielectric helical metamaterials are investigated both theoretically and experimentally and applied to different exciting new applications, such as in the design of new chiral nanowaveguides and nanocavities. The structurally induced strong chiroptical response of the dielectric nanohelices is tuned to different frequencies at the visible by varying their geometry. The fundamental understanding and experimental realization of the proposed new nanomaterials is expected to be transformative to the emerging field of chiral quantum optics.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.