Investigation of light conduction in single-wall and double-wall carbon nanotubes

TL;DR

This paper models light conduction in metallic carbon nanotubes as surface plasmon waves, deriving dispersion relations for single-wall and double-wall nanotubes, and explores the effects of relativistic electron beams on plasmon excitation.

Contribution

It introduces a theoretical model for light conduction in metallic CNs using 2D electron gas and Maxwell's equations, including effects of relativistic electron beams.

Findings

Derived dispersion relations for TE and TM modes in CNs.

Analyzed the impact of relativistic electron beams on surface plasmon creation.

Calculated frequencies, wavelengths, and group velocities of plasmon waves.

Abstract

Carbon Nanotubes (CNs) are made of tubular graphite layers. These macromolecules have interesting features which are generally introduced in the first chapter of the thesis. In the rest of the thesis, the light conduction in metallic CNs is investigated. In chapter 2, by modeling metallic single-wall CNs as 2D free electron gas layers, we find the density of electrons on a 2D electron gas and solve the Maxwell's equations for these cylindrical waveguides. We assume the same time-dependency or frequency for the electrons oscillations on the 2D gas layers and the propagating electromagnetic waves along the CNs. This assumption is the necessary condition for the light conduction with surface plasmons, that is, the only mechanism to conduct laser beams on nanoscale and below the diffraction limit of light. In chapters 3 and 4, we apply boundary conditions to the solutions of Maxwell's equations, and find the dispersion relations of single-wall and double-wall CNs for the transverse electric (TE) and transverse magnetic (TM) modes. In chapter 5, we investigate the effect of applying relativistic electron beams on singlewall and double-wall CNs to create surface plasmons, and calculate the dispersion relation ghraphs of CNs in the presence of fast electron beams. This yield the frequencies, wavelengths and group velocities of surface plasmon waves created by relativistic beams along CN metallic waveguides.