V. Lozovski

Lichtenecker's equation : applicability and limitations

Lichteneckers equation for the effective dielectric function is considered with the help of spectral representation. The spectral density function of resonances is determined and its behavior is analyzed. This analysis is carried out at different values of a parameter specifying the composite topology. It is shown that Lichteneckers equation describes a specific composite topology only. It is not reduced to the Bruggeman topology but may be represented as a spheroid system.

Effective dielectric response of a shape-distributed particle system

To calculate the effective dielectric response of a dilute composite, a generalization of the Maxwell Garnett theory for small nonspherical particles distributed in shape is proposed. Various types of distribution function are analysed and the applicability of the simplest (steplike) distribution is discussed. It is shown that the use of the steplike distribution is more valid for particles having a higher imaginary part of the permittivity in the actual region. Besides, an alternative approach to the problem based on the spectral representation is also considered. As an illustration, the effective dielectric response of a system of semiconductor (SiC) and metal (Al) ellipsoidal particles is calculated.

Susceptibilities of nano-particles at the surface of a solid

Abstract The self-consistent approach is proposed for calculation of an effective susceptibility of single nano-particle and nano-particle layer at a surface of a solid. This approach is based on exact summation of iteration procedure series, which is applied to solution of self-consistent equation for a local field. The condition when the layer can be considered as dilute one is discussed.

Near-field imaging of pyramid-like nanoparticles at a surface

Abstract An exact analytical solution of the self-consistent equation for the local field is used to calculate the near-field optical images of pyramid-like nano-objects placed at a surface of a solid. The diagram method developed previously for near-field image formation is generalized in order to describe layered objects, which are treated as many-body systems. The near-field optical images of triangular and square pyramids are calculated for the illumination configuration as well as those of triangular and square prisms. It is found that the near-field images of nanoparticles having the dielectric constant close to that of the substrate change rapidly and in a complicated manner with the probe–sample distance.

Self-Consistent Approach to Calculation of the Optical Response and Absorption Profiles of Thin Nanocomposite Films

The absorption profiles for different nanocomposite thin films are calculated in the frame of approach based on a local-field method for calculations of optical properties of nanocomposite thin films having a matrix topology. The electrodynamic interactions between the inclusions as well as inclusions-matrix interactions are explicitly taken into account. It is shown that the absorption spectra are strongly dependent both on inclusions concentration and on materials the nanocomposite is made of. The dependences of the effective dielectric functions of different nanocomposites on type of inclusions, and their volume fraction are analyzed. The optical properties of thin nanocomposite films with different distributions of identical spherical inclusions along the film thickness are studied.

Self-consistent description of electrodynamic interaction between two spheres: implications for near-field resonant interactions

The interaction between two spheres with the use of a macroscopic self-consistent approach allowing one to rigorously describe multiple scattering in near-field optics is considered. The implementation of this approach leads to the concept of the effective susceptibility of the scattering system that explicitly relates the incident field to the self-consistent field. We demonstrate that the approach developed can be advantageously used to determine the self-consistent field in systems with simple geometry. Considering two interacting spherical scatterers we show that the self-consistent fields inside the spheres, calculated with and without taking into account multiple scattering, differ noticeably at a resonance.

Influence of inclusion shape on light absorption in thin Au/Teflon nanocomposite films

Absorption profiles of thin Teflon films with gold spheroidal nanoinclusions are calculated in the framework of a local-field approach adapted for nanocomposite thin films with a matrix topology. Electrodynamic interactions between the inclusions and inclusion–matrix interactions are explicitly taken into account. The influence of the inclusion shape on the effective susceptibility of the film is analyzed. We assumed the light to be normally incident to the film surface and the axes of revolution of inclusion spheroids to be normal to the film surface as well. We study the dependence of the absorption spectra obtained on the volume fraction, shape, and distribution of inclusions across the film thickness. At a fixed volume fraction of the inclusions, the strongest contribution comes from the system in which the prevailing orientation of the longest linear dimension of inclusion particles matches the direction of the incident electric field. As a result, the most efficient absorption is achieved for inclusions shaped like oblate spheroids compared to prolate spheroids and spheres of the same volume.

Electrodynamical interactions inside a system of nano-particles

Abstract A self-consistent scheme for calculation of the effective susceptibility of a many-body nano-system is proposed. The scheme is based on the idea of pseudo-vacuum Green function. The recurrent expressions connecting the Green function of the n −1 particle system with that of n particle system are obtained. The general sum rule for the effective susceptibilities of a many-body system is discussed.

Magneto-optical Kerr effect in corrugated magnetoplasmonic heterostructures

We performed a detailed theoretical study of the magneto-optical polar Kerr effect in magnetoplasmonic heterostructures consisting of a plasmonic film and a ferromagnetic layer with a corrugated top surface. Explicit analytical expressions allowing us to calculate the modifications of the polar Kerr effect in dependence on the thickness of the plasmonic and ferromagnetic layers as well as on the period and depth of the corrugation were derived. Interestingly, when applied to the test system of an Au/Co bilayer, our calculations show that the presence of corrugations is beneficial, as it allows us to tailor the magneto-optical response in a magnetoplasmonic composite in a resonant manner. This opens the possibility to enhance the strength of the Kerr effect by several orders of magnitude, which is beneficial for the investigation of systems in which magneto-optical responses are rather small, i.e., for characterization of biological or medical systems.

Interaction between localized-on-nanoparticles plasmon polaritons and surface plasmon polaritons

An approach to describing of the excitation and propagation of the surface plasmon polaritons (SPPs) along the surface with the nanodisks that are located above them is proposed. In the framework of the proposed approach the dissipation function is calculated for the different geometry of the systems with the disks. The Fano-like antiresonance curves of absorption profiles have been obtained. The antiresonance absorption characteristics have been explained by the interaction between the SPP with the continuous spectrum and localized plasmon polaritons at the cylinders with the discrete spectrum. The obtained result is similar to the well-known Fano effect.