title: Three-dimensional plasmonic chiral tetramers assembled by DNA origami.
abstract: Molecular chemistry offers a unique toolkit to draw inspiration for the design of artificial metamolecules. For a long time, optical circular dichroism has been exclusively the terrain of natural chiral molecules, which exhibit optical activity mainly in the UV spectral range, thus greatly hindering their significance for a broad range of applications. Here we demonstrate that circular dichroism can be generated with artificial plasmonic chiral nanostructures composed of the minimum number of spherical gold nanoparticles required for three-dimensional (3D) chirality. We utilize a rigid addressable DNA origami template to precisely organize four nominally identical gold nanoparticles into a three-dimensional asymmetric tetramer. Because of the chiral structural symmetry and the strong plasmonic resonant coupling between the gold nanoparticles, the 3D plasmonic assemblies undergo different interactions with left and right circularly polarized light, leading to pronounced circular dichroism. Our experimental results agree well with theoretical predictions. The simplicity of our structure geometry and, most importantly, the concept of resorting on biology to produce artificial photonic functionalities open a new pathway to designing smart artificial plasmonic nanostructures for large-scale production of optically active metamaterials.
authors.affiliation: National Center for Nanoscience and Technology, No. 11 BeiYiTiao, ZhongGuanCun, Beijing 100190, China.
authors.forename: Xibo
authors.initials: X
authors.lastname: Shen
authors.forename: Ana
authors.initials: A
authors.lastname: Asenjo-Garcia
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Qiao
authors.initials: Q
authors.lastname: Jiang
authors.forename: F Javier
authors.initials: FJ
authors.lastname: García de Abajo
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.forename: Baoquan
authors.initials: B
authors.lastname: Ding
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D006046:Gold; D004247:DNA