Surface-Plasmon-enhanced density of optical states (DOS)

Evolution of the dispersion characteristics and DOS in nanostructured plasmonic materials. (a1-d1) Schematics of materials and nanostructures with various degrees of light and charge carriers confinement, including (a1) bulk isotropic dielectric, (b1) a metal-dielectric interface, (c1) thin-film-based and wire-based hyperbolic metamaterials (metal inclusions are golden-colored), and (d1) a spherical metal nanoparticle. (a2-d2) The dispersion relations for the structures shown in (a1-d1). In (b2), the red solid line corresponds to the bound SPP mode and the red dotted line to quasi-bound and propagating modes. The dispersion relations for a lossless metal-dielectric interface (dash blue) and bulk dielectric (solid grey) are also shown. The insets to (d2) show spatial intensity distributions of dipole and quadrupole LSP modes with the angular momentum quantum numbers and , respectively. (a3-d3) The momentum-space representations of the dispersion relations (iso-frequency surfaces), with allowed wavevectors shown as red arrows. In (d3), the three allowed values of the azimuthal momentum quantum number ( ) are shown for the dipole LSP mode ( ). (a4) DOS in the isotropic bulk dielectric with index as a function of photon energy (red line). The energy spectra of the terrestrial solar radiation and the blackbody thermal emission are shown in the background. (b4-d4) LDOS in the vicinity of the structures in (b1-d1) as a function of energy at varying distance from the metal interface. Figure 1 of "Plasmonic materials for energy: from physics to applications," Svetlana V. Boriskina, Hadi Ghasemi, Gang Chen, Materials Today, 10/2013; 16:379-390. DOI:10.1016/j.mattod.2013.09.003