On the Metasurface-Based Comb Filters

This letter reports a new type of plasmonic metamaterial-based comb filter with the metasurface as similar to the Salusbury window, and comprised of three layers - sub-wavelength-sized periodic gold nanorods surrounded by free-space (i.e., the metasurface), silicon, and silver nanolayers. The structure yields multiple absorption peaks upon impinged by electromagnetic waves. The metasurface behaves as a comb filter - certain spectral frequencies are absorbed and the remaining ones are reflected back. The performance of filter is analyzed in UV, visible, and near infrared (NIR) regimes considering the p- and s-polarized excitations under different angles of incidence.