Third harmonic generation of cosh-Gaussian laser beam in arrays of vertically aligned carbon nanotube

In this present study, we have theoretically investigated the enhanced cosh-Gaussian laser beam third harmonic generation via the nonlinear interaction with vertically aligned arrays of carbon nanotube. As a high power cosh-Gaussian laser interacts with carbon nanotube medium, the atoms of this nano dimension medium are quickly ionized and formed the performed plasma. Owing to passes of lighter mass electron cylinder as compared with the mass of ion cylinder, the electron cylinder might be displaced. The nonlinearity is raised due to electrostatic restoration force on electrons. This cosh-Gaussian laser beam has enough potential to imparts the oscillatory velocity to conducting electrons of nano tube and efficiently absorbed at the surface plasmon resonance frequency. Analytic expressions of nonlinear third harmonic current density and laser third harmonic field are derived. The plotted graphical profiles promise the efficient and tunable generation of laser third harmonic field via the variation of beam decentered parameter, laser beam width, nanotube radii, inter carbon nanotube separation, initial electric field amplitude of laser beam and electron-ion collisional frequency. Resonant field amplitude of laser third harmonic is observed at the laser beam frequency becomes 1/2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1/\sqrt 2$$\end{document} times of the electron plasma frequency. As the laser beam transverse propagation distance become near the 0.95 times the initial beam width, enhanced third harmonic field might be generated. The laser beam decentered parameter plays an effective role for field enhancement of third harmonic without change of laser beam frequency.