Propagation of three-dimensional bipolar ultrashort electromagnetic pulses in an inhomogeneous array of carbon nanotubes

TL;DR

This paper investigates how 3D bipolar ultrashort electromagnetic pulses behave in inhomogeneous carbon nanotube arrays, showing they can reflect or pass through regions with higher electron concentration and potentially form stable 3D solitons.

Contribution

It introduces a model for 3D ultrashort pulse propagation in inhomogeneous nanotube arrays and demonstrates conditions for reflection, transmission, and soliton-like stability.

Findings

Pulses can be reflected or transmitted depending on parameters.

Ultrashort pulses can propagate over long distances without spreading.

Potential formation of 3D electromagnetic solitons in nanotube arrays.

Abstract

We study the propagation of three-dimensional (3D) bipolar ultrashort electromagnetic pulses in an inhomogeneous array of semiconductor carbon nanotubes. The heterogeneity is represented by a planar region with an increased concentration of conduction electrons. The evolution of the electromagnetic field and electron concentration in the sample are governed by the Maxwell's equations and continuity equation. In particular, non-uniformity of the electromagnetic field along the axis of the nanotubes is taken into account. We demonstrate that, depending on values of parameters of the electromagnetic pulse approaching the region with the higher electron concentration, the pulse is reflected from the region or passes it. Specifically, our simulations demonstrate that, after interacting with the higher-concentration area, the pulse can propagate steadily, without significant spreading. The possibility of such ultrashort electromagnetic pulses propagating in arrays of carbon nanotubes over distances significantly exceeding characteristic dimensions of the pulses makes it possible to consider them as 3D solitons.