Aspects of metamaterial structures : theory and simulation

King, NJ

Abstract

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.

Citation

King, N. Aspects of metamaterial structures : theory and simulation. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2007