281 research outputs found
Manipulation of Giant Faraday Rotation in Graphene Metasurfaces
Faraday rotation is a fundamental magneto-optical phenomenon used in various
optical control and magnetic field sensing techniques. Recently, it was shown
that a giant Faraday rotation can be achieved in the low-THz regime by a single
monoatomic graphene layer. Here, we demonstrate that this exceptional property
can be manipulated through adequate nano-patterning, notably achieving giant
rotation up to 6THz with features no smaller than 100nm. The effect of the
periodic patterning on the Faraday rotation is predicted by a simple physical
model, which is then verified and refined through accurate full-wave
simulations.Comment: 4 pages, 5 figures, submitted to Applied Physics Letter
Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave Antennas
published_or_final_versio
Seismic Waveguide of Metamaterials
We have developed a new method of an earthquake-resistant design to support
conventional aseismic designs using acoustic metamaterials. We suggest a simple
and practical method to reduce the amplitude of a seismic wave exponentially.
Our device is an attenuator of a seismic wave. Constructing a cylindrical
shell-type waveguide that creates a stop-band for the seismic wave, we convert
the wave into an evanescent wave for some frequency range without touching the
building we want to protect.Comment: 4 pages, 4 figure
Magneto-electric dipole antenna based on differentially-excited composite right/left-handed (CRLH) transmission lines
A new magneto-electric (ME) dipole antenna array is proposed which provides a combined electric- and magnetic-dipole response in a planar configuration. The proposed structure is based on Composite Right/Left-Handed (CRLH) transmission lines, which is differentially fed and operated in the zeroth-order regime to provide maximal gain for the combined radiators. The basic principle of the proposed ME-dipole antenna is discussed and demonstrated with full-wave simulation results. © 2013 IEEE.published_or_final_versio
Reverse Doppler Effect of Sound
We report observation of reverse Doppler effect in a double negative acoustic
metamaterial. The metamaterial exhibited negative phase velocity and positive
group velocity. The dispersion relation is such that the wavelength
corresponding to higher frequency is longer. We observed that the frequency was
down-shifted for the approaching source, and up-shifted when the source
receded
Topological bands in two-dimensional networks of metamaterial elements
We show that topological frequency band structures emerge in two-dimensional
electromagnetic lattices of metamaterial components without the application of
an external magnetic field. The topological nature of the band structure
manifests itself by the occurrence of exceptional points in the band structure
or by the emergence of one-way guided modes. Based on an EM network with nearly
flat frequency bands of nontrivial topology, we propose a coupled-cavity
lattice made of superconducting transmission lines and cavity QED components
which is described by the Janes-Cummings-Hubbard model and can serve as
simulator of the fractional quantum Hall effect
Quasi-discrete microwave solitons in a split ring resonator-based left-handed coplanar waveguide
We study the propagation of quasi-discrete microwave solitons in a nonlinear
left-handed coplanar waveguide coupled with split ring resonators. By
considering the relevant transmission line analogue, we derive a nonlinear
lattice model which is studied analytically by means of a quasi-discrete
approximation. We derive a nonlinear Schr{\"o}dinger equation, and find that
the system supports bright envelope soliton solutions in a relatively wide
subinterval of the left-handed frequency band. We perform systematic numerical
simulations, in the framework of the nonlinear lattice model, to study the
propagation properties of the quasi-discrete microwave solitons. Our numerical
findings are in good agreement with the analytical predictions, and suggest
that the predicted structures are quite robust and may be observed in
experiments
L'utilisation des SIG dans la modélisation en hydrologie de surface
From a methodological point of view, hydrological modelling
appears to offer a great potential for spatial analysis. However
among classes of models, only physical models consider the
spatial dimension as a variable. The topography and the land
cover are the two major spatial components involved in that
type of models. The production of a relevant DTM requires the
use of iterative interpolation procedures. Land cover and its
changes can be monitored and entered into modelling from
remote sensing images through a normalized Vegetation index. The GIS approach can be integrated at different levels
within hydrological modelling, with object oriented GIS seen
as the highest level
Wave Energy Amplification in a Metamaterial based Traveling Wave Structure
We consider the interaction between a particle beam and a propagating
electromagnetic wave in the presence of a metamaterial. We show that the
introduction of a metamaterial gives rise to a novel dispersion curve which
determines a unique wave particle relationship, via the frequency dependence of
the metamaterial and the novel ability of metamaterials to exhibit simultaneous
negative permittivity and permeability. Using a modified form of Madey's
theorem we find that the novel dispersion of the metamaterial leads to a
amplification of the EM wave power
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