Dissertation > Excellent graduate degree dissertation topics show

Studies on Nonlinear Properties of a Left-Handed Material

Author: ZhangYangLi
Tutor: WangZhengPing
School: Harbin Engineering University
Course: Optics
Keywords: left-handed materials nonlinear effects negative permeability kerr effect
CLC: O441.6
Type: Master's thesis
Year: 2009
Downloads: 64
Quote: 2
Read: Download Dissertation

Abstract

Left-handed material is a new type of artificial material with simultaneously negative permittivityεand permeabilityμ. Compared with regular materials, left-handed materials have a variety of unusual electromagnetic properties as follows:reversed Doppler shift, Cherenkov radiation, negative refraction, perfect lens effect and so on. In 1968, Veselago introduced the concept of left-handed materials, but no known materials exist in nature with simultaneously negativeεandμ, left-handed materials have remained a curious exercise in electromagnetic theory. Until 30 years later, with the development of artificial periodic materials, scientists have theoretically and experimentally proved the possibility of realization of left-handed materials, respectively. The discovery of left-handed materials has been regarded as one of the ten most significant discoveries in science community in 2003, and has been the front and focus area in physics and electromagnetics research.For many years, most research work on left-handed materials mainly focus on their linear properties, where both the permittivity and permeability of the materials were assumed to be independent of the strengths of external electric and magnetic fields. In 2003, Zharov et al first analyzed the nonlinear properties of a left-handed material, and he pointed out that, when the incident electromagnetic field strength is large enough, nonlinear properties of the materials should be taken into account. These results have excited great interests of people to research into nonlinear eft-handed materials.At present, the research work on nonlinear left-handed materials mainly focus on the generalization of existing nonlinear optics branches, such as second harmonic generation, optical soliton properties, ultra-short pulse transmission properties and so on. However, the nonlinear properties of some special structural left-handed materials have not been studied in detail.So in view of such situation, the main work in this thesis is that though studying the nonlinearity of a two-dimensional micro-structure created by arrays of wires and split-ring resonators embedded into a nonlinear dielectric, gave the relation between the nonlinear permeability and the parameters of this structure on the variation of external magnetic field.The results show that, the structure can switch between left-handed materials and right-handed materials under different conditions. And change the the parameters of this structure, the nonlinear hysteresis response of the permeability depending on external field changed a lot, which can be equivalent to choosing proper strength of external magnetic field strength at a certain frequency range. This phenomenon may be used to realize the micro-wave or optical switching devices.

Related Dissertations

CLC: > Mathematical sciences and chemical > Physics > Electromagnetics,electrodynamics > Electricity and Magnetism > Electromagnetic properties of substances
© 2012 www.DissertationTopic.Net Mobile