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We present systematic numerical calculations of plexcitonic properties of a linear chain comprised of quantum emitters - metal nanoparticle dimers interacting in the strong coupling regime. The calculations are based on a recently developed semi-analytical technique based on a multiple-scattering polaritonic-operator formalism in conjunction with an electromagnetic coupled dipole method. Based on this method, we calculate the two main features corresponding to the formation of plexcitonic chain modes: the primary plexcitonic resonance as well as the corresponding Rabi splitting associated with the generation of an avoided-crossing area. We apply an exponential model to the numerical results obtained via the above technique to describe the plexciton redshift induced with increasing chain length. We also identify an asymptotic plexciton frequency at a chain length of approximately 20 dimers. A model Hamiltonian is employed to assess the energy splitting defined by the avoided crossing area of the main plexciton resonance which is found to scale as where N is the number of dimers in the chain. [ABSTRACT FROM AUTHOR]

We present a theoretical study for the Kerr nonlinearity of a four-level double-V-type quantum system near a two-dimensional array of metal-coated dielectric nanospheres. In the quantum system under study one V-type transition is influenced by the interaction with surface plasmons while the other V-type transition interacts with free-space vacuum. The quantum system interacts with a linearly polarized weak laser field that couples the lowest state with the upper states in the free-space transitions. We show that the Kerr nonlinearity is strongly influenced by the presence of the plasmonic nanostructure and is particularly sensitive to the distance between the quantum system and the plasmonic nanostructure. [ABSTRACT FROM AUTHOR]

In this paper, we present a new class of 3D metamaterials that exhibit artificial magnetism and/or negative refractive index. These metamaterials consist of spherical particles made from strongly resonant materials such as ionic/semiconductor materials and noble metals. Their electromagnetic response is studied using the extended Maxwell–Garnett effective medium theory and an ab initio method based on multiple scattering theory. The agreement between both treatments is very good, rendering the effective medium approximation a useful guide for the experimentalist in the field. [ABSTRACT FROM AUTHOR]

We investigate theoretically the non-Markovian dynamics of a degenerate V-type quantum emitter in the vicinity of a metallic nanosphere, a system that exhibits quantum interference in spontaneous emission due to the anisotropic Purcell effect. We calculate numerically the electromagnetic Green's tensor and employ the effective modes differential equation method for calculating the quantum dynamics of the emitter population, with respect to the resonance frequency and the initial state of the emitter, as well as its distance from the nanosphere. We find that the emitter population evolution varies between a gradual total decay and a partial decay combined with oscillatory population dynamics, depending strongly on the specific values of the above three parameters. Under strong-coupling conditions, coherent population trapping can be observed in this system. We compare our exact results with results when the flat continuum approximation for the vacuum modified by the metallic nanosphere is applied. We conclude that the flat continuum approximation is an excellent approximation only when the spectral density of the system under study is characterized by nonoverlapping plasmonic resonances. [ABSTRACT FROM AUTHOR]