Asymmetric Light Scattering on Heterodimers Made of Au Nanorods Vertically Standing on Au Nanodisks

Abstract Directional light control at nanoscale shows great potential in applications such as holograms, optical neural networks, and ultracompact photonic circuits. Plasmonic nanostructures with designed geometrical shapes or complex architectures have been employed to manipulate light directionally. The interaction among the electric dipole and multipole resonances in plasmonic nanostructures enables the wavefront reshaping of light, leading to directional light scattering behaviors. However, traditional methods for directional light control suffer from complicated fabrication procedures and large footprints. In this work, heterodimers are constructed out of chemically grown Au nanodisks and Au nanorods, with the nanorod sitting vertically on the nanodisk, and their directional light scattering behaviors are studied. When the nanorod is located off the center of the nanodisk, the incident light is scattered asymmetrically by the heterodimer, producing a crescent‐shaped far‐field scattering pattern. The light scattering directionality of the heterodimers is further proved to be highly dependent on the aspect ratio of the nanorod, the relative position of the two nanocrystals, and the orientation of the nanorod. The study provides a solid and useful foundation for the directional light manipulation in ultracompact nanophotonic systems.