All Optical Nanostructed Sensor Based on Metal-Dielectric-Metal Plasmonic Waveguide

Based on a two-dimensional plasmonic metal-dielectric-metal waveguide with a thin metallic layer and dual nanocavites inserted in the core, a novel nanostructured absorber is presented. A transfer matrix model for the proposed structure is established, and the optical spectra are investigated. Design results show that a narrow reflection spectrum occurs at position of the near-unity absorption, and is significantly influenced by the environment. It is able to generate a sensitivity as high as 1000 nm/RIU, which be used as an excellent sensing platform for chemical and biochemically relevant molecules.