Faculty of Physics, Ludwig-Maximilians-University, Munich, Germany.
Zuse Institute Berlin, Berlin, Germany.
Nat Commun. 2021 Apr 1;12(1):2025. doi: 10.1038/s41467-021-22289-8.
Circular dichroism (CD) has long been used to trace chiral molecular states and changes of protein configurations. In recent years, chiral plasmonic nanostructures have shown potential for applications ranging from pathogen sensing to novel optical materials. The plasmonic coupling of the individual elements of such metallic structures is a crucial prerequisite to obtain sizeable CD signals. We here identify and implement various coupling entities-chiral and achiral-to demonstrate chiral transfer over distances close to 100 nm. The coupling is realized by an achiral nanosphere situated between a pair of gold nanorods that are arranged far apart but in a chiral fashion using DNA origami. The transmitter particle causes a strong enhancement of the CD response, the emergence of an additional chiral feature at the resonance frequency of the nanosphere, and a redshift of the longitudinal plasmonic resonance frequency of the nanorods. Matching numerical simulations elucidate the intricate chiral optical fields in complex architectures.
圆二色性（CD）长期以来一直用于追踪手性分子状态和蛋白质构象变化。近年来，手性等离子体纳米结构在病原体传感到新型光学材料等领域的应用中显示出了潜力。这些金属结构的各个元件的等离子体耦合是获得可观的 CD 信号的关键前提。我们在这里确定并实现了各种耦合实体，包括手性和非手性实体，以证明在近 100nm 的距离上进行手性转移。通过位于一对金纳米棒之间的非手性纳米球来实现耦合，该纳米棒使用 DNA 折纸术以手性方式排列得很远。发射粒子会引起 CD 响应的强烈增强，在纳米球的共振频率处出现附加的手性特征，以及纳米棒的纵向等离子体共振频率的红移。匹配的数值模拟阐明了复杂结构中的复杂手性光学场。
