2 research outputs found
Manipulating Electromagnetic Fields with Advanced Metamaterials
In almost any scientific experiment, we take into account some
particular properties of materials, e.g. electromagnetic,
mechanical, thermal, etc. These properties determine a majority
of the physical phenomena that arise from the interaction with
matter, and thus restrict potential applications of natural
materials. The discovery and subsequent development of novel
materials regularly boost the standards of living through new
technological progress and cutting-edge research. One of the very
recent and promising discoveries is related to the field of
metamaterials - artificially structured media with subwavelength
patterning. These artificial materials offer a unique platform
with large flexibility and unusual properties for tailoring
acoustic and electromagnetic waves, including novel ways for the
manipulation of light. In this thesis, I employed the concept of
metamaterials for both the study of new physical phenomena
related to the emerging field of topological photonics and also
develop innovative applications of specific metamaterials for the
advancing the magnetic resonance imaging (MRI) machines.
Chapter 1 provides an introduction to the field of metamaterials
and their unusual properties, starting from the definition of
meta-atoms and expanding to more complex structures, including
one-dimensional meta-chains and metasurfaces. This is followed by
an introduction to the fields of topological photonics and
magnetic resonance imaging techniques. The experimental
approaches based on a microwave platform are also described.
Finally, the thesis motivation and structure are summarized.
Chapter 2 presents experimental studies of topological features
of zigzag arrays of dielectric particles. It includes the first
experimental observation of the subwavelength photonic
topological edge states, topological phase transition in the
chains of dielectric particles, as well as, the study of the
specific features of the photonic spin Hall effect mediated by
the excitation of the subwavelength topological edge states.
Chapter 3 describes the study of bianisotropic metasurfaces and
metamaterials. The experimental designs of bianisotropic metallic
and dielectric metasurfaces are presented, with a direct
observation of topologically nontrivial edge states. Further, it
is revealed how to couple topologically protected metasurfaces to
form three-dimensional all-dielectric topologically nontrivial
bianisotropic metamaterials and metacrystals.
Chapter 4 focuses on the study metasurfaces based on resonant
arrays of metallic wires used for advancing magnetic resonance
imaging (MRI) characteristics. A new conceptual idea for the
substantial enhancement of signal-to-noise ratio of a 1.5T MRI is
presented. This approach is further developed and extended to
ultra-high field MRI (7T) where a direct evaluation of the
metasurface properties is examined during in-vivo human brain
imaging.
Chapter 5 summarizes the results and concludes the thesis