High Power Laser Interaction with Nanotubes and Nanoparticlesquot

Abstract

The proposed thesis endeavors to study collective free electron behavior in carbon newlinenanotubes and nanoparticles and examine their impact on electromechanical properties, second newlineharmonic generation, terahertz radiation generation, anomalous heating, nonlinear absorption, newlinenonlinear current density, field emission, X-Mode Propagation, Raman scattering, Brillouin newlinescattering, Linear and Nonlinear Response and nonlinear absorption of light at high power laser newlineinteraction. newlineWe propose a new scheme of terahertz radiation generation employing a matrix of newlineanharmonic carbon nanotube (CNTs) embedded on silica substrate. The matrix is irradiated by two newlinecollinear laser beams that induce large excursion of CNT electrons and exert a nonlinear force at newlinethe beat frequency and#969;=and#969;1-and#969;2. The force drives a nonlinear current producing THz radiation. The newlineTHz field is resonantly enhanced at the plasmon resource,and#61559; and#61501;and#61559;p (1and#61483;and#61538; ) / 2 , where and#969;p is plasma newlinefrequency and and#61538; is a characterizing parameter. Collisions are a limiting factor suppressing the newlineplasmon resonance. For typical parameters, we obtain power conversion efficiency of the order of newline10-6. newlineWe develop an analytical formalism of nonlinear laser absorption in a nanorod embedded newlinedielectric surface. The nanorods lie in the plane of the dielectric, in the form of a planer array. The newlinenanorods lie in the plane of the dielectric, in the form of a planer array. The laser, impinged on newlinethem with electric field perpendicular to the lengths of the nanorods, imparts oscillatory velocity newlineto nanorod electrons. As the free electrons of a nanorod are displaced, a space charge field is newlinevii newlinedeveloped in the nanorod, exerting a restoration force on the electrons. The electron drift velocity newlineshows a resonance atand#61559; and#61501;and#61559;p 2 , where p and#61559; denotes the plasma frequency of free electrons inside newlinethe nanorod. The resonance is inhibited by collisions and nanorod expansion. At the resonance, the newlineelectrons are efficiently heated by the laser and laser energy is strongly absorbed, resulting in newlinesignificant reduction in laser tra