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Electromagnetic Metamaterials
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Electromagnetic Metamaterials and their
Approximations:
Practical and Theoretical Aspects
CSIC Building (#406),
Seminar Room 4122.
Directions: home.cscamm.umd.edu/directions
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Some Ideas to
Manipulate Waves using the
Transformation Media Concept
Professor
Che
Ting Chan
Hong Kong University of Science
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Abstract:
We suggest a way to manipulate electromagnetic waves
by introducing a rotation mapping of coordinates
that can be realized by a specific transformation of
the permittivity and permeability of a shell
surrounding an enclosed domain. This kind of
transformation media rotates the information for a
fixed angle, so that observers inside/outside the
rotation coating would see a rotated world with
respect to each other, and the existence of the
shell is not detectable. Various reduced form of
implementation is considered, including a layered
system involving alternating layers of metals and
dielectrics. Experiments in the microwave regime
were carried out to demonstrate the rotation effect
happens in a broad frequency range.
We consider extending the idea of cloaking to
acoustic waves. In two dimension, the solution is
readily obtained by mapping the acoustic equations
to the Maxwells equations of one polarization in the
2D geometry. We find that the acoustic equation can
be mapped to the DC conductivity equation in 3D,
which then allows the design of 3D acoustic cloaking
using the coordinate transformation scheme. The
perfect cloaking effect of such a cloak is confirmed
by solving for the scattering problem using the
spherical-Bessel function series expansion method.
We will also discuss other issues such as the
possibility of extending the bandwidth of the
invisibility cloak, the energy transport velocity
inside the cloak and whether the invisibility cloak
based on transformation media can really hide
everything inside.
*Work done in collaboration with H.Y. Chen. Work
supported by a Central Allocation Grant. |
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