Broadband unidirectional scattering in the transverse direction and angular radiation realized by using a silicon hollow nanodisk under a radially polarized beam

In recent years, directional scattering has been one of the most active research hotspots in the field of nanophotonics. Herein, we study the directional scattering properties of a silicon hollow nanodisk illuminated by a tightly focused radially polarized beam. The induced strong longitudinal total electric dipole interferes with transverse magnetic dipole to achieve a highly-efficient transverse unidirectional scattering when the silicon hollow nanodisk is located at a specific position in the focal plane. Moreover, the manipulated unidirectional scattering in the transverse direction can be realized in the broad wavelength range from 581 nm to 656 nm. In addition, the unidirectional angular radiation towards all directions can be realized by adjusting the position of the silicon hollow nanodisk. Our research results are helpful for the design of nanophotonic devices that can manipulate the angular radiation direction, and have potential applications in sensing, optical communications, solar cells and other fields.