Directional Plasmonic Excitation by Helical Nanotips

The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e., scattering, and a discrete one, such as surface plasmon excitation, leads to Fano-like resonance lineshapes. The necessary phase matching requirements can be used to engineer the light–plasmon coupling and to achieve a directional plasmonic excitation. Here, we investigate this effect by using a chiral nanotip to excite surface plasmons with a strong spin-dependent azimuthal variation. This effect can be described by a Fano-like interference with a complex coupling factor that can be modified thanks to a symmetry breaking of the nanostructure.

Directional Plasmonic Excitation by Helical Nanotips

The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, like a nanoparticle or a nanohole, the coupling between a broadband effect, i.e. scattering, and a discrete one such as surface plasmon excitation, leads to Fano-like resonance lineshapes. The necessary phase matching requirements can be used to engineer the light-plasmon coupling and to achieve a directional plasmonic excitation. Here we investigate this effect by using a chiral nanotip to excite surface plasmons with a strong spin-dependent azimuthal variation. This effect can be described by a Fano-like interference with a complex coupling factor that can be modified thanks to a symmetry breaking of a nanostructure.

Directional excitation of surface plasmon using multi-mode interference in an aperture

Plasmonics is a promising technology that can find many applications in nanophotonics and biosensing. Local excitation of surface plasmons with high directionality is required for many of these applications. We demonstrate that by controlling the interference of light in a metal slot with the adjustment of the angle of incidence, it is possible to achieve highly directional surface plasmon excitation. Our numerical analysis of the structure showing a strong directionality of excited surface plasmon is confirmed by near field scanning measurements. The proposed structure can be useful for many applications including excitation of plasmonic waveguides, nanolithography, and optical sensing. To illustrate its usefulness, we experimentally demonstrate that it can be used for highly directional excitation of a dielectric loaded plasmonic waveguide. We also propose a simple structure for surface plasmon interference lithography capable of providing high image contrast using this scheme.

Improving the rate of the copper-catalyzed Henry reaction by surface plasmon excitation of Gold nanoparticles

Green LED plasmon excitation (525 nm) of colloidal gold nanoparticles (NPs), onto which a copper(II) complex was grafted, in the presence of nitrobenzaldehyde and nitromethane in DMF lead to the...

Surface Plasmon Resonance Sensors for Concentration and Reaction Kinetic Detections

Surface plasmon resonance (SPR) is an optical phenomenon that occurs on the metal (normally gold or silver) film surface and the light that excited this phenomenon changes with the refractive index of materials on the metal surface. SPR sensors are constructed based on this phenomenon and are used in fields of biological and chemical analyses, drug screening, environmental monitoring, and so on. Here, we will make an introduction to applications of SPR sensors on reaction kinetic and concentration detections. To make this chapter readily comprehensible, we will divide it into three portions. The first part will be an abbreviated depiction of surface plasmon excitation and constructions of an SPR sensor. Then, we will aim at an introduction to the bimolecular interactions in SPR sensors. At last, we will make a summary on applications of SPR sensors.