Gold Nanograils with Tunable Dipolar Multiple Plasmon Resonances

Gold nanograils, novel plasmonic nanostructures that can be represented as three different-sized rings connected vertically by curved surfaces, similar to a miniaturized grail, are presented. Reflectance measurements and FDTD simulations demonstrate the existence of strong multiple plasmon resonances with the same dipolar symmetry around the sharp ring edges of the nanograils.