Polarizabilities of spherical subwavelength silica glass particles are investigated having regard to material dispersion. It is shown that the ranges of the negative electric and magnetic polarizabilities almost coincide. This allows the particles in question to be used for producing media with a negative refractive index.

In this paper, an algorithm for designing of the metafilms consisting of nonidentical spherical particles with given spectral properties is proposed. A solution is constructed analytically, and the algorithm can be easily implemented in natural experiment.

The spectral characteristics of a set of square planar arrays of spherical ferroelectric barium titanate particles embedded in extruded polysterene foam have been investigated. Considerable differences are observed between the measured transmission and reflection coefficients and the corresponding calculated values for a metafilm with identical particles. This discrepancy is caused by the statistical variance of the resonant frequencies of spherical particles. Good agreement with experimental data is obtained by statistical averaging of the calculated parameters of metafilms over an ensemble of ideal arrays.

The reflection and transmission coefficients of metafilms composed of U-shaped resonators were obtained in the frequency range of 0.1 - 1 THz by numerical finite-element simulation method. The side length, the gap depth and the period of resonators were proportionally scaled. The experimental spectra of the transmission coefficients for metafilms with U-shaped resonators were received. The re-tuning of the resonant modes was shown from 0.12 till 0.51 THz at the geometric parameters scaling.

In this paper we study the influence of the period between U-shaped split-ring resonators (SRRs) on the transmission/absorbtion properties and refraction index of metasurfaces in THz frequency range (0.1 - 1 THz) using experiments and numerical simulations. The metasurfaces are formed by U-shaped SRRs arrays. The period varies from 63 to 300 mu m The metasurface electromagnetic responses are obtained using terahertz time-domain spectroscopy. The experimental and numerical results reveal the shift in transmission spectra for the metasurface response and the tuning of absorbtion intensity at the period between U-shaped SRRs changing. The notable change in the metasurface refractive index is shown.

A numerical algorithm is designed and implemented based on the joint application of the finite-difference time-domain (FDTD) method with absorbing boundary conditions (a combination of the perfectly matched layer (PML) and Mur first-order conditions) and the total-field/scattered-field technique (TF/SF). A complete formulation of the algorithm is given. The results of computing the spectral characteristics of the 2D photonic crystal with defects in the form of waveguides are presented. They demonstrate that it is possible to conduct calculations in a wide range of frequencies.

Size dependences of the eigenfrequencies, quality factors and polarizabilities of small metallic particles-resonant radiating elements were examined. Limits of electrodynamic scaling regions and ones of plasmon oscillations predominance were established for two types of particles-spling-ring and core-shell resonators.