Effective boundary conditions, in the form of two-sided impedance boundary conditions, are formulated for the linear electrodynamics of single- and multishell carbon nanotubes (CN’s). The impedance is derived using the dynamic conductivity of CN’s, which is obtained for different CN’s (zigzag, armchair, and chiral) in the frame of the semiclassical as well as quantum-mechanical treatments. Propagation of surface waves in CN’s is considered. The phase velocities and the slow-wave coefficients of surface waves are explored for a wide frequency range, from the microwave to the ultraviolet regimes. Relaxation is shown to qualitatively change the dispersion characteristics in the low-frequency limit, thereby rendering the existence of weakly retarded plasmons impossible. A dispersionless propagation regime is shown possible for the surface waves in the infrared regime. Attenuation and retardation in metallic and semiconductor CN’s are compared.

The Leontovich-Levin equation for optical scattering by an achiral carbon nanotube (CNT) of finite length is formulated, based on a quantum-mechanical microscopic model of the conductivity. Both approximate analytical and numerical solutions of the Leontovich-Levin equation yield a comparable surface current density distribution and scattering pattern. Applications over a wide frequency range from the terahertz to the ultraviolet are possible. The CNT polarizability in the low-frequency range and the scattering pattern in the range of optical interband transitions as well as in the vicinity of plasmon resonance are calculated. Geometric resonances of strongly retarded surface waves emerge and can be used for the qualitative interpretation of experimentally observed features in the optical response characteristics of CNT-based composite mediums. The potential of isolated CNTs as optical nanoantennas of both the receiving and transmitting types is established.

Thanks to its high electrical conductivity, a graphene plane presents a good shielding efficiency against GHz electromagnetic radiations. Several graphene planes separated by thin polymer spacers add their conductivities arithmetically, because each of them conserves the intrinsic properties of isolated graphene. Maximum absorption of radiations for frequency around 30[emsp14]GHz is achieved with six separated graphene planes, which is the optimum number. This remarkable result is demonstrated experimentally from electromagnetic measurements performed in the Ka band on a series of multilayers obtained by piling 1, 2, 3 [mldr] graphene/PMMA units on a silica substrate. Theoretical calculations convincingly explain the observed absorption and transmission data in the GHz domain. It is concluded that graphene/PMMA multilayers can be used as an efficient optically transparent and flexible shielding media.

A model for the effective conductivity of a dilute and disordered composite material containing randomly single-wall carbon nanotube (SWCNT) inclusions was formulated. The modification of electron transport by the surface curvature of SWCNTs and an axial depolarization effect due to the finite length of metallic SWCNTs are taken into account. Simultaneous consideration of both effects permits the correct interpretation of the dependences of the effective conductivity on the frequency and temperature, and explains an experimentally observed terahertz peak in the spectrum of the effective conductivity.

The propagation of azimuthally symmetric guided waves in multiwalled carbon nanotubes (MWCNTs) was analyzed theoretically in the midinfrared and the visible regimes. The MWCNTs were modeled as ensembles of concentric, cylindrical, conducting shells. The influence of intershell electron tunneling on the optical properties of MWCNTs was examined by focusing on a double-walled carbon nanotube (DWCNT). Longitudinal electrostatic waves exist in DWCNTs due to intershell tunneling. Conditions for weak influence of intershell tunneling in DWCNTs were identified, and an integral-equation approach for scattering by an MWCNT was formulated when those conditions prevail. Slightly attenuated guided waves and antenna resonances due to the edge effect exist for not-too-thick MWCNTs in the far-infrared and the midinfrared regimes. Interband transitions retard the propagation of guided waves and have a deleterious effect on the performance of a finite-length MWCNT as a nanoantenna. Propagation of surface-plasmon waves along an MWCNT with a gold core was also analyzed. In the near-infrared and the visible regimes, the shells behave effectively as lossy dielectrics to suppress surface-plasmon-wave propagation along the gold core.

Experimental proof of localized plasmon resonance was found in thin films containing either single-walled carbon nanotubes (SWNT) or SWNT bundles of different length. All samples were prepared by a simple technique that permitted the selection of different SWNT lengths in different samples without significant differences in electronic properties. Fourier-transform infrared spectroscopy showed that an optical-density peak, the same as a terahertz conductivity peak, shifts to higher frequencies as the SWNT lengths are reduced—in agreement with a similar tendency predicted for the localized plasmon resonance in finite-length SWNTs [Slepyan et al., Phys. Rev. B 81, 205423 (2010)].