Nanostructures for surface plasmons

Abstract

Surface plasmons (SPs) are electromagnetic excitations existing at the interface between a metal and a dielectric material. Control and manipulation of light based on SPs at the nanometer scale offers significant advantages in nanophotonic devices with very small elements, since the peculiar properties of SPs can be tailored by construction of nanostructures with various interfaces between metals and dielectric materials. Recent progress in nanostructures for SPs is reviewed. Resonance frequencies or wavelengths of SPs can be tuned by design of metal nanostructures, such as nanoparticles, nanorods, nanowires, nanosheets, and nanodisks. Moreover, SP resonance modes can also be tuned by control of the shapes and sizes of nanostructures, where the resonance modes include longitudinal and transversal resonances, dipolar and multipolar resonances, and Fano resonances. Based on SP coupling for metal nanostructures, metal–semiconductor nanostructures, metal–dielectric nanostructures, and metal–polymer nanostructures, propagating and guiding of SP can be achieved through the metal nanostructures and the hybrid structures. Additionally, metal nanostructures exhibit remarkable field enhancement effects (e.g., local near-field enhancement, and optical transmission enhancement) due to SP coupling. Furthermore, SP nanostructures perform unique focusing and imaging characteristics at the nanometer scale beyond the diffraction limit. Tailoring SPs by control of the nanostructures is expected to be used for design and development of high-performance optical components and circuits, which offer both potential and challenges for new generations of nanophotonic devices.