2,906 research outputs found
Transformation Optics for Plasmonics
A new strategy to control the flow of surface plasmon polaritons at metallic
surfaces is presented. It is based on the application of the concept of
Transformation Optics to devise the optical parameters of the dielectric medium
placed on top of the metal surface. We describe the general methodology for the
design of Transformation-Optical devices for surface plasmons and analyze, for
proof-of-principle purposes, three representative examples with different
functionalities: a beam shifter, a cylindrical cloak and a ground-plane cloak.Comment: 15 pages, 3 figure
Transformation optics in orthogonal coordinates
The author proposes the methodology of transformation optics in orthogonal
coordinates to obtain the material parameters of the transformation media from
the mapping in orthogonal coordinates. Several examples are given to show the
applications of such a methodology by using the full-wave simulations.Comment: 23 pages, 4 figure
A Unified Approach to Nonlinear Transformation Materials
The advances in geometric approaches to optical devices due to transformation
optics has led to the development of cloaks, concentrators, and other devices.
It has also been shown that transformation optics can be used to gravitational
fields from general relativity. However, the technique is currently constrained
to linear devices, as a consistent approach to nonlinearity (including both the
case of a nonlinear background medium and a nonlinear transformation) remains
an open question. Here we show that nonlinearity can be incorporated into
transformation optics in a consistent way. We use this to illustrate a number
of novel effects, including cloaking an optical soliton, modeling nonlinear
solutions to Einstein's field equations, controlling transport in a Debye
solid, and developing a set of constitutive to relations for relativistic
cloaks in arbitrary nonlinear backgrounds
Ultra directive antenna via transformation optics
Spatial coordinate transformation is used as a reliable tool to control
electromagnetic fields. In this paper, we derive the permeability and
permittivity tensors of a metamaterial able to transform an isotropically
radiating source into a compact ultradirective antenna in the microwave domain.
We show that the directivity of this antenna is competitive with regard to
conventional directive antennas horn and reflector antennas, besides its
dimensions are smaller. Numerical simulations using finite element method are
performed to illustrate these properties. A reduction in the electromagnetic
material parameters is also proposed for an easy fabrication of this antenna
from existing materials. Following that, the design of the proposed antenna
using a layered metamaterial is presented. The different layers are all
composed of homogeneous and uniaxial anisotropic metamaterials, which can be
obtained from simple metal-dielectric structures. When the radiating source is
embedded in the layered metamaterial, a highly directive beam is radiated from
the antenn
General Relativistic Contributions in Transformation Optics
One potentially realistic specification for devices designed with
transformation optics is that they operate with high precision in curved
space-time, such as Earth orbit. This raises the question of what, if any, role
does space-time curvature play in determining transformation media?
Transformation optics has been based on a three-vector representation of
Maxwell's equations in flat Minkowski space-time. I discuss a completely
covariant, manifestly four-dimensional approach that enables transformations in
arbitrary space-times, and demonstrate this approach for stable circular orbits
in the spherically symmetric Schwarzschild geometry. Finally, I estimate the
magnitude of curvature induced contributions to satellite-borne transformation
media in Earth orbit and comment on the level of precision required for
metamaterial fabrication before such contributions become important.Comment: 14 pages, 3 figures. Latest version has expanded analysis,
corresponds to published versio
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