Terahertz radiation generation process in the medium based on the array of the noninteracting nanotubes

Abstract

Consideration of periodically alternating arrays of noninteracting carbon nanotubes with the metal type of conductivity as elements of the quantum layer heterostructures (quantum wells), which will play the role of the active field, is suggested. From the earlier obtained results based on the models of the elementary cell, it follows that the system in the neighborhood of the Dirac points at the presence of the longitudinal electric field will have equidistant spectrum. The eigenvalues of the energies do not depending on the longitudinal electric field. The two-component eigenfunctions do not depend on the longitudinal electric field. The amplification of the generation terahertz radiation by the analogy with the cascade lasers in the multilevel medium, based on the system of the noninteracting metallic carbon, is considered. If concentration of the nanotubes is 10 7 cm -2 then the output power per unit area will be about Q $ n 0 k 0 hxJ k =e % 8 W=cm 2 . The wavelength of the terahertz radiation is 65 lm.

Terahertz radiation generation process in the medium based on the array of the elongated nanoparticles

“…First we consider the array of chiral nanotubes as the nonlinear media and then generalise the obtained results for the array of armchair-edge nanoribbons. The theoretical part of the task for the zigzag nanotubes is viewed in [36], in which the analytically obtained results in [39] are used. In [39] on account of an elementary phase cell, which contains sublattice A and sublattice B, the wave functions, equidistant energy levels and dipole matrix elements of laser transition in the presence of a longitudinal electric field are analytically obtained.…”

“…Where ˆ, H    is the commutator of Hamilton operator Ĥ . We use equation (2.1) (where 1 T is the longitudinal time relaxation; 2 T is the transverse relaxation time) and then write the interaction of a classical optical field with a multilevel system with the use of density matrix formalism as) [36,35] …”

“…In [35] the author's approach combines the tight-binding model with the continuum model of kp-type to investigate finite length graphene nanoribbon with armchair edges subjected to the external electric field longitudinal to the edges and derive approximate solutions for the electron energies and wave functions around the Dirac point. In the work on the simulation of a cascade laser similar to [28,36] it is shown that generation of terahertz radiation is possible at reasonable experimental parameters. It is also discussed how generation of radiation by Cherenkov mechanism is possible [37].…”

“…The paper focuses on a theoretical study and numerical simulation of the task of amplification of terahertz radiation by analogy with QC lasers in medium, based on non-interacting armchair edge nanoribbons with metallic conductivity, and on the estimation of the value of generating radiation and the value of radiative current density. The case of noninteracting metallic nanotubes for non-densely and randomly distributed composites of particles is discussed in [36]. The effective dielectric function in the geometrical model arrays is defined by the individual particle polarizability with consideration to the geometry of the array (geometric factor).…”

Terahertz Radiation Generation Process In The Medium Based On The Array of The Elongated Nanoparticles

“…[36] [36]. In Ref [36]. current for the ballistic transport is determined in accordance with the Landauer formula (3.8)[46,47].…”