Generation and Propagation of Electromagnetic Waves in Carbon Nanotubes: New Propositon for Optoelectronics and Bio‐medical Applications

Abstract

Electromagnetic response properties of carbon nanotubes (CNTs) are discussed. A basic approach to the problem is proposed synthesizing present‐day solid‐state physics and classical electrodynamics of nonhomogeneous mediums.[1] The developed theoretical model predicts the property of CNTs to be a strong slowing‐down system for surface waves[1,2] and allows proposing the physical schemes of the carbon nanotube use as monomolecular optoelectronic devices, such as a surface wave waveguide in IR frequency range, a monomolecular optical nanoantenna, a nanoantenna excitation device based on the Purcell effect, etc. A particular emphasis is given to the stimulated emission of electromagnetic waves by electron beam in nanotube. The significant retardation of the surface wave along with the ballistic character of the electron motion in nanotubes are shown[3] to be underlying the idea of the monomolecular light emitter with the Cherenkov lasing mechanism: the electrons in nanotube imposed to a realistic voltage can be accelerated to the velocities synchronous with the phase velocity of the surface wave. Since the achievable current density in nanotubes exceeds drastically corresponding characteristic values in vacuum electronic devices, the stimulated emission in CNTs is started at a very small, of the order of several microns, length of electron‐photon interaction. A dispersion equation for the electron beam instability in a nanotube is presented and analyzed. The potential of carbon nanotube as traveling wave tube (TWT) and backward wave oscillator (BWO) is demonstrated.