Aspects of metamaterial structures: Theory and simulation
King, NJ 2007, Aspects of metamaterial structures: Theory and simulation , PhD thesis, Salford : University of Salford.
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The investigations reported here address the issue of overcoming loss in a typical isotropic metamaterial. The possibility of adding functionality to such materials, through gyrotropic effects, and diffraction management of nonlinear beams, driven by negative phase accumulation, is presented. Loss is overcome by the introduction of gain to the metamaterial. This is achieved on the basis that typical split-ring metaparticles can be suitably enhanced through the addition of carefully selected diodes. The detailed analysis given here deploys a familiar equivalent circuit model and specific current-voltage characteristics. It is emphasised that conditions must be in place to ensure overall stable material behaviour. The methodology uses convective and absolute instability concepts and it is shown that the latter can be so detrimental as to lead to a much reduced frequency window of operation. Another set of investigations emphasises that surface waves provide a path to new science. Consequently the propagation of surface waves along the interface between a metamaterial and a gyrotropic medium is promising for applications. The investigation outcomes of this complicated system need to demonstrate generation properties in real time. Hence, some unique finite-difference time-domain (FDTD) computations have been developed enabling their interesting connection to the Goos- Hanchen shift to be elegantly displayed. Many interesting forms of surface waves are discussed including the simultaneous generation of TE and TM waves propagating in opposite directions. It is well known that in an isotropic metamaterial backward waves can exist so this property is exploited to create a fascinating form of diffraction management. This is investigated both for the bulk and for cavities and the impact of what is defined as nonlinear diffraction is introduced. Finally, some magnetooptics is introduced that adds even more functionality to the generation of cavity solitons.
|Item Type:||Thesis (PhD)|
|Schools:||Colleges and Schools > College of Science & Technology > School of Computing, Science and Engineering|
|Depositing User:||Institutional Repository|
|Date Deposited:||03 Oct 2012 14:34|
|Last Modified:||20 Aug 2013 18:33|
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