N. V. Grishina

Analysis of plasmonic resonances of two paired noble metal spheroids via the discrete sources method

A modified scheme of the discrete sources method has been applied to investigate the strong interaction between proximal noble metal nanoparticles. The new scheme enables calculation of a near-field enhancement of several orders with a high degree of accuracy. The total field enhancement in between two spheroidal particles and the scattering cross-section have been analyzed in the frequency domain depending on the separation distance, spheroid aspect ratio, equivolume diameter, and material. In particular, it has been found that spheroids of smaller size can produce larger field enhancement than larger ones. Simulation results demonstrate that it is possible to achieve localized surface plasmon resonance at any desired exciting wavelength by using an appropriate geometrical configuration and material of the coupled spheroids.

Analysis of the effect of an extremal energy transmission through a conducting film with a nano-sized inset

The effect of an extremal transmission of electromagnetic energy through a film from a noble metal with a cylindrical inset is analyzed both in the spatial and spectral regions using the discrete-sources method. The results of computer simulation allow one to establish the mechanism by which this phenomenon occurs. A physical interpretation of this phenomenon is given.

Relationship between strict and approximate models in the problem of transformation of evanescent waves

The transformation of evanescent waves near a layered substrate is considered. A comparative analysis of results obtained on the basis of rigorous and approximate approaches is performed. It is shown that the use of approximate models may lead to erroneous results.

Discrete sources method for light scattering analysis from 3D asymmetrical features on a substrate

Abstract The discrete sources method is extended to analyze polarized light scattering by three-dimensional asymmetrical features on a plane penetrable substrate. The strict mathematical model and corresponding numerical scheme are described. Computer simulation results of non-spherical micro-particle scattering show that particle shape has a stronger effect on measured response for normal incident scanners.

Analysis of plasmon resonances of closely located particles by the discrete sources method

Based on a modification of the discrete sources method, a detailed analysis of plasmon resonances of closely located particles is performed. The numerical algorithm makes it possible to calculate the near field with a high degree of accuracy and to trace resonances at which both the cross section and the intensity of the near field increase by several orders of magnitude.

Discrete source method for analysis of fluorescence enhancement in the presence of plasmonic structures

A mathematical model of fluorescence enhancement in the presence of a plasmonic structure is examined by applying a modified discrete source method that takes into account the nonlocal interaction between the elements of the plasmonic structure. The fluorescence quantum yield is computed using a generalization of the optical theorem to the case of a local excitation source. The elements of the plasmonic structure are optimized in order to maximize the fluorescence enhancement factor.

Study of Extraordinary Scattering of Evanescent Waves by the Discrete Sources Method

The discrete sources method was adapted to analyze the scattering properties of particles located on a layered substrate. Resonances of the scattering cross section near the total internal reflection angles were detected in a numerical experiment. It was shown that the resonance amplitude can be controlled via an additional thin transparent layer deposited on the film.

Analysis of double surface plasmon resonance by the discrete source method

The discrete source method is modified in order to mathematically simulate and study the scattering properties of nonspherical particles located on the surface of a conducting film deposited on a glass prism. Both differential and integral scattering properties of metal nanoparticles are examined. It is shown that the scattering cross section behind the film can be increased by 107 times by deforming the particle and shifting it with respect to the film. It is also shown that the scattered intensity distribution in the prism is localized in two directions, forming sharp narrow fingers with the intensity exceeding the incident wave amplitude by 15–30 times.

Analysis of Spatial Resonances in the Field of Evanescent Waves by the Discrete Source Method

Scattering properties of particles placed on a metal film deposited on a glass prism are studied in detail using a computer implementation of the discrete source method. The presence of scattering cross-section resonances in the region of angles of incidence of a plane wave has been established. The possibility of controlling the radiation directionality in the resonance range is demonstrated. Conditions that permit one to increase the resonance intensity by an order of magnitude have been found.

Investigation of plasmon resonances in local structures by the discrete sources method

The modification of the Discrete Sources Method, which allows one to perform effective numerical analysis of plasmon resonances in local structures, is proposed and realized. The numerical algorithm allows computation of the near field with a high degree of accuracy and tracking resonances that cause an increase of the near-field intensity by several orders of magnitude.