We study the topological edge plasmon modes between two diatomic chains of identical plasmonic nanoparticles. Zak phase for longitudinal plasmon modes in each chain is calculated analytically by solutions of macroscopic Maxwells equations for particl
es in quasi-static dipole approximation. This approximation provides a direct analogy with the Su-Schrieffer-Heeger model such that the eigenvalue is mapped to the frequency dependent inverse-polarizability of the nanoparticles. The edge state frequency is found to be the same as the single-particle resonance frequency, which is insensitive to the separation distances within a unit cell. Finally, full electrodynamic simulations with realistic parameters suggest that the edge plasmon mode can be realized through near-field optical spectroscopy.
We show that the scattering interaction between a high energy electron and a photon can be strongly enhanced by different types of localized plasmons in a non-trivial way. The scattering interaction is predicted by an eigen-response theory, numerical
ly verified by finite-difference-time-domain simulation, and experimentally verified by cathodoluminescence spectroscopy. We find that the scattering interaction associated with dark plasmons can be as strong as that of bright plasmons. Such a strong interaction may offer new opportunities to improve single-plasmon detection and high-resolution characterization techniques for high quality plasmonic materials.
We show that under the presence of a static magnetic field the photon eigen-frequencies of a circular gyromagnetic cylinder experience a splitting that is proportional to the angular momentum density of light at the cylinder surface. Such a splitting
of the photonic states is similar to the Zeeman splitting of electronic states in atoms. This leads to some unusual decoupling properties of these non-degenerate photonic angular momentum states, which are demonstrated through numerical simulations.
We study the group velocity of light in layer-by-layer chiral photonic crystals composed of dielectrics and metals. Through studying the band structures with an extended-zone scheme that is given by a Fourier analysis, we show the existence of negati
ve group velocity in the proposed chiral structures. The physical mechanism is interpreted with the help of a simplified model that has an analytical solution. The iso-frequency contours of the photonic band structure suggest that the negative group velocity can lead to either positive or negative refraction, depending on the orientation of the medium interface. We propose a feasible realization of such kind of photonic crystals. Computational results on the proposed realization are consistent with that of the simplified models.
