Robust existence of the broadband optical transmission effect in multiple-layer gratings

Abstract

We numerically demonstrate the existence and robustness of the broadband optical transmission (BOT) effect in double-layer gratings (DLGs) with different longitudinal spacings and lateral displacements. For the two scenarios of large and ultrasmall longitudinal spacings, the different physical mechanisms by which BOT occurs through the gaps between the two layers are analyzed based on the surface charge densities. Besides the DLG structures, the robustness of the BOT phenomenon can also be extended to exist in multiple-layer gratings with more layers. This provides a highly controllable way to design novel devices, such as transparent multiple-layer metals, broadband metamaterials, and novel polarization filters.