Demydenko Y. Surface electromagnetic waves in the layers adsorbed on the surface of a solid.

The thesis presents a theory of electromagnetic phenomena in solid-state systems with adsorbed molecular coverings in which the possibility of generation of surface electromagnetic waves (SEWs) was investigated and demonstrated the possibility of existence of new kinds of SEWs. These waves bear characteristic signs of a molecular covering on the surface of a solid. A distinguishing characteristic of these SEWs is the possibility of their generation by means of both (p- and s-) polarizations of an electromagnetic field in the area of frequencies where the dielectric function of an adsorbent is negative. For cases of adsorption of a molecular layer at the isotropic dielectric or semiconductor surface the spectrum of SEWs was investigated. It was found that for the case of a resonant interaction of molecular oscillations with the field of a surface excitation of the adsorbent there is a possibility of appearance of a gap. Gap magnitude is determined by nature and parameters of the covering.The effect of concentration "softening" of the p- polarized wave was discovered for the case of adsorption of polyatomic molecules at the dielectric surface as a result of intermolecular interactions. The effect is a necessary condition for formation of an inhomogeneous state in the polarized system of an adsorbate. For the system of spherically-isotropic molecules adsorbed on the isotropic dielectric substrate it was demonstrated the possibility of spontaneous formation of the periodically polarized structure in an adsorbed layer as a result of intermolecular interactions. The parameters of such a structure were estimated. For a molecular layer with a periodical distribution of polarization the influence of the period of distribution on formation of dispersion spectrum of SEWs was investigated. A possibility of management of the dispersion behavior of SEWs was demonstrated for the molecular layer on the surface of nonlinear medium which acts as a phase conjugator for the probe beam in the four-mixing scheme. It was found agap in absorption spectrum of the p- polarized SEW when a molecular layer is adsorbed on the semiconductor surface. The gap is caused by the molecular layer and is an analogue to that in the absorption spectrum of photonic band gap systems.