Plasmonic characteristics of nanorod-based metallic nanostructures

The plasmonic characteristics of four types of nanorods based metallic nanostructures, including parallel-nanorod, U-shaped, ∩-shaped and π-shaped nanostructures, are numerically investigated using finite difference time domain (FDTD) method. In the visible and near infrared regions, their extinction spectra are different according to the morphologies of the nanostructures and the separations of their longitudinal nanorods. Under the same plane continuous wave (CW) illumination, their electromagnetic field distributions show nodal fields inside the nano-waveguides formed by the nanostructures. Under the same focal beam illumination, all of the four nanostructures exhibit waveguiding effect which transports the energy of the focuses to a long distance, but by different resonance modes which depending their configurations. The proposed nanorod-based nanostructures behave as surface enhanced nano-waveguides which can find intriguing application in nano-photonic devices.

► Four types of nanostructures are numerically investigated using FDTD method. ► Electromagnetic field distributions show nodal fields inside the nano-waveguides. ► In focusing field they show different transmission efficiencies for focus energy. ► π-shaped nanostructure can transfer the optical field with bend legs.