title: Janus magneto-electric nanosphere dimers exhibiting unidirectional visible light scattering and strong electromagnetic field enhancement.
abstract: Steering incident light into specific directions at the nanoscale is very important for future nanophotonics applications of signal transmission and detection. A prerequisite for such a purpose is the development of nanostructures with high-efficiency unidirectional light scattering properties. Here, from both theoretical and experimental sides, we conceived and demonstrated the unidirectional visible light scattering behaviors of a heterostructure, Janus dimer composed of gold and silicon nanospheres. By carefully adjusting the sizes and spacings of the two nanospheres, the Janus dimer can support both electric and magnetic dipole modes with spectral overlaps and comparable strengths. The interference of these two modes gives rise to the narrow-band unidirectional scattering behaviors with enhanced forward scattering and suppressed backward scattering. The directionality can further be improved by arranging the dimers into one-dimensional chain structures. In addition, the dimers also show remarkable electromagnetic field enhancements. These results will be important not only for applications of light emitting devices, solar cells, optical filters, and various surface enhanced spectroscopies but also for furthering our understanding on the light-matter interactions at the nanoscale.
authors.affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, ‡Guangdong Province Key Laboratory of Display Material and Technology, and §School of Physics and Engineering, Sun Yat-sen University , Guangzhou 510275, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Pu
authors.initials: P
authors.lastname: Liu
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Ke
authors.forename: Yunkun
authors.initials: Y
authors.lastname: Su
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Ningsheng
authors.initials: N
authors.lastname: Xu
authors.forename: Shaozhi
authors.initials: S
authors.lastname: Deng
authors.forename: Huanjun
authors.initials: H
authors.lastname: Chen
keywords: dimer; electromagnetic field enhancement; magnetic resonance; plasmon; unidirectional light scattering