The optical response of nanostructures that exhibit pronounced plasmonic effects is studied and analyzed. Various
approaches to solve light scattering problems in the time domain and in the frequency domain, using both the domain
and the boundary discretization methods were used. Far-field and near-field characteristics of plasmonic nanostructures
are investigated with several numerical algorithms to study the shape effect and the effects of the illumination angles on
the resonance behavior. Numerical results with high accuracy, reduced complexity and reduced computational time due
to extensive use of semi-analytical solutions are obtained. This set of numerical experiments demonstrates significant
differences in the performances of different numerical methods. We observed that even simple geometries of plasmonic
nanostructures may pose severe problems for various methods. We identify a strong need to select and modify numerical
simulation algorithms according to the plasmonic effects, in addition to the standard selection of numerical method
according to the geometrical settings and length scales.
Antireflective coatings are useful for a range of applications, from minimizing the radar cross-section of stealth
aircraft, to maximizing the efficiency of solar energy panels. New low-index nanorod thin films promise broadband,
broad angle performance for such coatings. We demonstrate that a bandwidth increase from 38.5% to 113% is possible by using a simple evolutionary strategy to optimize the thin film material parameters. A two dimensional FDTD planewave periodic scattering approach is used to demonstrate additional performance increase by adding losses to a single layer. The same technique may be used for antireflective coatings for which no analytical solution exists, as is the case with dispersive, non-linear materials, special geometries, and coatings with metallic or ferromagnetic inclusions. A procedure is outlined for using the FDTD approach to obtain a map of reflection coefficients with respect to wavelength and incidence angle.