FIG. 1. (a) Sketches of the excitations of surface plasmons polaritons - SPP (top), localized surface plasmons - LSP (middle), and magnetic plasmons - MP (bottom). All these excitations are associated with a collective motion of surface charges under light illumination. (b) Diagram of MP-based plasmonic nanostructures used for fundamental studies and their applications in various research fields.
Topics: Electromagnetism, Magnetism, Metamaterials, Nanoclusters, Nanomaterials, Plasmonic Nanostructures
The magnetic response of most natural materials, characterized by magnetic permeability, is generally weak. Particularly in the optical range, the weakness of magnetic effects is directly related to the asymmetry between electric and magnetic charges. Harnessing artificial magnetism started with a pursuit of metamaterial design exhibiting magnetic properties. A plasmonic nanostructure called split-ring resonators gave the first demonstration of artificial magnetism. Engineered circulating currents form magnetic plasmons, acting as the source of artificial magnetism in response to external electromagnetic excitation. In the past two decades, magnetic plasmons supported by plasmonic nanostructures have become an active topic of study. This Perspective reviews the latest studies on magnetic plasmons in plasmonic nanostructures. A comprehensive summary of various plasmonic nanostructures supporting magnetic plasmons, including split-ring resonators, metal–insulator–metal structures, metallic deep groove arrays, and plasmonic nanoclusters, is presented. Fundamental studies and applications based on magnetic plasmons are discussed. The formidable challenges and the prospects of the future study directions on developing magnetic plasmonic nanostructures are proposed.