![]() Lastly, a parallel FDTD method was also used to model another interesting coordinate transformation based device, an optical black hole, which can be characterised as an omnidirectional broadband absorber. The finiteness of such a nano-device and its impact on the system dynamic behaviour was numerically exploited. the permittivity of particles calculated from dielectric parameters on the. In contrast to metals where charges are free to move throughout the material, in dielectrics all the charges are attached to specific atoms and molecules. The dielectric properties of polystyrene-polypyrrole (PS-PPy) core-shell. For example, an analytical expression for the electric potential produced by a point charge located inside and outside of a cylindrical pore studied by Cui. Section 4: Electrostatics of Dielectrics Dielectrics and Polarizability There aretwo large classes of substances: conductors andinsulators (or dielectrics). In recent decades, microstructural design in inorganic dielectrics, such as ferroelectrics, relaxor ferroelectrics and antiferroelectrics, have been extensively studied by domain engineering, grain regulation and the artificial design of core-shell or multilayer structures22,38-44. The device has its potential in subwavelength imaging at optical frequencies. So far, only a few of researches were investigated the method of image charges to study of cylindrical structures. Furthermore, a parallel three-dimensional dispersive FDTD method was introduced to model a plasmonic nanolens. These new devices demonstrate super-absorptivity over a moderate wideband range, suitable both for microwave and optical applications. It was found that, by utilising inherent electric and magnetic losses of metamaterials, as well as additional lossy materials, perfect wave absorption can be achieved. ![]() Several ways to control and manipulate the loss in the electromagnetic cloak based on transformation electromagnetics were examined. Finally, more useful cloaking structures were proposed, which can operate over a broad frequency spectrum. The limitations of all these devices were thoroughly studied and explored. By the mean of the effective mass approximation (E.M.A) and compact density matrix method, the energy eigenvalues, linear and nonlinear dielectric function have been theoretically investigated for CdS/ZnS cylindrical core/shell quantum dot embedded in PVA, PMMA and SiO 2 matrices. With a few modifications the method is able to simulate general media, such as concentrators and rotation coatings, which are produced by means of coordinate transformations techniques. It was demonstrated that perfect ``invisibility'' from electromagnetic cloaks is only available for lossless metamaterials and within an extremely narrow frequency band. ![]() The proposed method can accurately model both lossless and lossy cloaks with ideal or reduced parameters. For wavelengths close to these leaky modes, the nanowires act as cylindrical cavity that confines this radiation (see Figure 2.2 (a)). A novel radially-dependent dispersive FDTD algorithm was proposed and applied to simulate electromagnetic cloaking structures. During this PhD study, several finite-difference time-domain (FDTD) methods were developed to numerically investigate coordinate transformation based metamaterial devices.
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