Low Dimensional Plasmons Of Solid And The Coupling Of Electromagnetic Waves With Plasmons

As low-dimensional structures such as quantum wells, quantum wires, quantum dots and semiconductor superlattices have received durable attention and became one of the frontier research fields in condensed matter physics in recent years, plasmons in the low-dimensional electron gas has also been studied extensively. Plasmons are the quantum of the collective excitations of free electrons in solids. Experimental and theoretical studies of plasmons have mainly focused on the excitation energies and dispersion relations. Nanophotonics, near-field photonics, electromagnetic enhanced transmission and absorption, and metamaterials, by virtue of plasmons, have attracted numerous attention.The dispersion relation of the longitudinal plasmons was obtained firstly by David Pines and David Bohm using the random phase approximation (RPA). Then the hydrodynamical description and self-consistent linear response approximation (SCLRA), etc, were developed to describe the plasma oscillations in condensed matters. In the second part of this thesis, the plasmons dispersion relations for one-, two- and three-dimensional electron gas are compactly derived in two approaches with uniform disturbed Coulomb potentials. First approach is adopted usually in solid theory that is the so called random phase approximation (RPA) with the Lindhard dielectric function in the long-wavelength and high-frequency limits. Second method is a typical plasma fluid description that is the electron fluid equations with the adiabatic process in the jellium model. The disturbed electrostatic (Coulomb) potential produced by the oscillation of electron density is dimensional dependent and derived from the Poisson equation in detail.In the third part, surface plasmons in quasi-2D electron gas (confined in the metal or semiconductor surface) and surface plasmons polaritons (SPPs) are described systematically, as well as the effective plasmons modes for periodic structures built of very thin wires and effective surface plasmons on highly conducting surfaces perforated by holes are analyzed. In the last part, enhanced microwave transmission around surface plasmons resonance frequencies through subwavelength apertures in metallic structures is demonstrated, as well as the significant advancement of using plasmonic and metamaterial covers for shield。Microwave plasmonic shield as an invaluable method is emerging.