Novel approaches to control the propagation of electromagnetic waves : metamaterials and photonic crystals
Author
Bulu, İrfan
Advisor
Özbay, Ekmel
Date
2007Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Applications in areas such as photonics, antennas, imaging and optics require
the control of propagation of electromagnetic waves and the control of emission of
electromagnetic radiation. Achievements in three key research fields may provide
the answer to these problems. These emerging research fields are metamaterials,
photonic crystals and surface plasmons. This thesis will be about our work on
metamaterials and photonic crystals. Metamaterials are a new class of artificial
structures whose electromagnetic response can be described by effective permeability
and permittivity functions that may attain negative values. I will present
our results on the properties of a metamaterial structure that we proposed recently,
the labyrinth structure. I will demonstrate that the labyrinth structure
can be used to design a medium that exhibits negative permeability values within
a certain frequency range. Moreover, I will explore the possibility of negative refraction
and sub-wavelength focusing of electromagnetic waves by two and threedimensional
labyrinth structure based left-handed mediums. Novel applications
such as metamaterial based compact size antennas, ultra-small high-Q cavities
will be also discussed. Another type of artificial electromagnetic structures are
the photonic crystals. Photonic crystals can be described by a periodic modulation
of the permittivity and/or the permeability of a medium. I will discuss
two phenomena arising from the dispersion properties of photonic crystals and
their possible applications. One of these phenomena is the existence of surfacebound
electromagnetic modes and the other is the negative refraction effect. I
will further show that the surface-bound modes can be used for applications such
as beaming of electromagnetic waves and enhancement of transmission through
sub-wavelength apertures. In addition, I will demonstrate that the negative refraction
effect can be utilized to focus electromagnetic waves emitted from a finite
size source.
Keywords
Metamaterialenhanced transmission
beaming
surface mode
sub-wavelength focusing
negative refraction
plasma frequency
labyrinth structure
photonic crystal