Download تاريخ: 8/12/86‏

Thesis Title:
Date of Defense: 11/2/2008
Open Metamaterial Waveguides
and Nonlinear Magnetic Properties
Student Name: Farid-Al-Din Fayazbakhsh
Student Number: 84702373
Program of Study: Master of Science
Field of Study: Communication
Thesis Advisor: Dr. Mahmoud Akbari
Thesis Co-Advisor: Dr. Amir Ahmad
Shishegar
Keywords:
1- Left-Handed Material (LHM)
2- Negative Refraction
3- Surface Plasmon modes
4- Nonlinear Hystersis-like Behavior
5- Self-Phase Modulation
Abstract
Achieving artificial electromagnetic structures
with favorable and tunable properties is one of the
greatest interests of researchers all over the years.
A specific new branch of these structures known as
metamaterial has attracted particular attention
especially since last years of 20’s century, due to
their exciting features which can not be found in
natural materials, such as left-handed behavior,
negative refraction, etc. Furthermore, new
interesting and ever-increasing applications in
science and technology –such as making superlenses, sub-wavelength waveguides and resonators,
invisible cloak and antireflection layers and so onhas made this branch of science a very active and
hot branch of physics and electromagnetic in these
years.
We, in this thesis, had reviewed the physics of
metamaterials in the context of a historical aspect,
will investigate two kinds of metamaterial
waveguide structures (specifically metamaterial
slab and circular metamaterial waveguide known
as meta-fiber). Guided modes of each waveguide
including ordinary modes and surface plasmon
modes with their dispersion diagrams has been
derived and compared with those of an ordinary
right-handed waveguides. We also, investigated
the origin of nonlinear behavior of metamaterial
structures and their magnetic permeability model
in the vicinity of nonlinearity, noting their
hystersis-like behavior in nonlinear regime. The
frequency-dependence of critical magnetic fields in
the hystersis diagrams has been calculated for the
first time in the literature. Self-phase modulation
which is a well-known phenomenon in natural
materials with electric nonlinearity can be found in
metamaterials with magnetic nonlinear behavior,
but in its own way. We have shown the evolution
of a modulated Gaussian pulse in a nonlinear bulk
metamaterial encountering blue and red shifts or
equivalently spectral broadening due to self-phase
modulation.