Enhanced Optical Transmission through a Hybrid Bull's Eye Structure Integrated with a Silicon Hemisphere

In this work, we demonstrate a novel structure that can generate extraordinary optical transmission with a silicon hemisphere placed on a conventional bull's eye structure. There is a single subwavelength aperture surrounded by concentric periodic grooves on a substrate. The extraordinary optical transmission in this work is realized by the coupling of the surface plasmon polaritons in the periodic grooves and the localized electromagnetic field generated by the Mie resonance in the silicon hemisphere. The maximum normalized-to-area transmission peak can reach up to 662 with a decreasing device area and size. The electromagnetic field distribution at different geometry parameters is analyzed to clarify the mechanisms of the work in this paper. Additionally, the use of dielectric material in the aperture can avoid ohmic losses of metal material compared with the conventional one, which may suggest that a wider range of bull's-eye-structure applications is possible.