Kadygrob D. Surface and waveguide Josephson plasma modes in layered superconductors

In the dissertation, the dispersion characteristics of surface and waveguide Josephson plasma electromagnetic waves in layered superconductors are theoretically studied and a series of new phenomena associated with their excitation are predicted. In layered superconductors, due to the strong anisotropy of the current density of the Josephson plasma, one can observe new effects that cannot be observed in other conducting media. In particular, two branches of the dispersion curves for surface Josephson plasma waves in layered superconductors appear due to the anisotropy. Specifically, within the frequency gap in the spectrum of surface waves, the negative refraction of bulk waves can be observed in layered superconductors. The enhanced transmissivity of modulated thick slabs of layered superconductors (with thicknesses significantly exceeding the skin depth) for terahertz radiation due to the diffraction of the incident wave and the resonance excitation of the eigenmodes is considered. It is shown that a series of resonance peaks can be observed in the dependence of the transmittance on the varying incidence angle іnstead of a single peak observed in isotropic metals. The opposite effect of the resonance suppression of the transparency is predicted for the modulated thin plates of layered superconductors. This effect is caused by the excitation of localized eigenmodes.