Optical effects of multipole interaction in aggregated structures: Rigorous scattering solution for a periodic chain of cylinders

Anisotropic scattering effects of a gyrotropic sphere characterized using the T-matrix method

Solutions for characterizing both electromagnetic wave propagation in, and scattering by, a gyrotropic sphere are obtained based on some recently published literature. Both gyrotropic permittivity and permeability tensors are considered herein, and both transmitted internal fields and scattered external fields are derived theoretically. Compared with problems of a uniaxial sphere, a gyroelectric sphere, and a gyromagnetic sphere, the scattering problem considered here is found to be astonishingly complicated but more generalized in formulation and solution procedure. Numerical validations are made by reducing our results to a gyromagnetic sphere and comparing them with the results obtained using the Fourier transform method, where excellent agreements are observed. Then, radar cross sections (RCSs) versus electric and magnetic gyrotropy ratios are computed, while hybrid effects due to both electric and magnetic gyrotropies are studied extensively, where some special cases of uniaxial spheres are demonstrated. It is shown that characteristics of gyrotropy parameters in Cartesian coordinates may lead to considerably large variations in RCS values, elucidating physical significance of gyrotropy and anisotropy ratios in scattering control. The generalized formulation of the problem is expected to have wide practical applications, while some features of this gyrotropic sphere may help other researchers or engineers to understand more physical insight. In addition, some critical mistakes made in literature were corrected.

Infrared optics of structured metal-insulator particulates

We show that rodlike particulates structured from interleaving layers of metal and insulator (or semiconductor) can exhibit novel infrared and far infrared characteristics that are tunable through the control of their geometric parameters. Results of scattering and absorption calculations are presented which demonstrate the validity of approximating the dielectric constant of the layered material by its effective medium value, thereby simplifying the prediction of the infrared properties. By clarifying the origin of the infrared absorption peaks, it is shown that the positions of the peaks are dependent on the transverse dimension of the particles as well as on the insulator dielectric constant and its relative fraction. The infrared characteristics of the structured particulates are contrasted with those of the metal, the insulator, and the semiconductor.