164 research outputs found
Magnetic and Electric Excitations in Split Ring Resonators
We studied the electric and magnetic resonance of U-shaped SRRs. We showed
that higher order excitation modes exist in both of the electric and magnetic
resonances. The nodes in the current distribution were found for all the
resonance modes. It turns out that the magnetic resonances are the modes with
odd-number of half-wavelength of the current wave, i.e. 1/2, 3/2 and 5/2
wavelengths modes, and the electric resonances are modes with integer number of
whole-wavelength of current wave, i.e. 1, 2 and 3 wavelengths modes. We
discussed the electric moment and magnetic moment of the electric and magnetic
resonances, and their dependence to the length of two parallel side arms. We
show that the magnetic moment of magnetic resonance vanishes as the length side
arms of the SRR reduces to zero, i.e. a rod does not give any magnetic moment
or magnetic resonance.Comment: Journal-ref and DOI link adde
Effective material parameter retrieval for thin sheets: theory and application to graphene, thin silver films, and single-layer metamaterials
An important tool in the field of metamaterials is the extraction of
effective material parameters from simulated or measured scattering parameters
of a sample. Here we discuss a retrieval method for thin-film structures that
can be approximated by a two-dimensional scattering sheet. We determine the
effective sheet conductivity from the scattering parameters and we point out
the importance of the magnetic sheet current to avoid an overdetermined
inversion problem. Subsequently, we present two applications of the sheet
retrieval method. First, we determine the effective sheet conductivity of thin
silver films and we compare the resulting conductivities with the sheet
conductivity of graphene. Second, we apply the method to a cut-wire
metamaterial with an electric dipole resonance. The method is valid for
thin-film structures such as two-dimensional metamaterials and
frequency-selective surfaces and can be easily generalized for anisotropic or
chiral media.Comment: 5 pages, 5 figure
Surface Plasmon Driven Electric and Magnetic Resonators for Metamaterials
Using interplay between surface plasmons and metamaterials, we propose a new
technique for novel metamaterial designs. We show that surface plasmons
existing on thin metal surfaces can be used to "drive" non-resonant structures
in their vicinity to provide new types of electric and magnetic resonators.
These resonators strictly adhere to surface plasmon dispersion of the host
metal film. The operating frequency of the resultant metamaterials can be
scaled to extremely high frequencies, otherwise not possible with conventional
split-ring-resonator-based designs. Our approach opens new possibilities for
theory and experiment in the interface of plasmonics and metamaterials to
harvest many potential applications of both fields combined.Comment: Less than 5 Journal Pages, 5 Figure
Strong group velocity dispersion compensation with phase-engineered sheet metamaterials
Resonant metamaterials usually exhibit substantial dispersion, which is
considered a shortcoming for many applications. Here we take advantage of the
ability to tailor the dispersive response of a metamaterial introducing a new
method of group-velocity dispersion compensation in telecommunication systems.
The method consists of stacking a number of highly dispersive sheet
metamaterials and is capable of compensating the dispersion of optical fibers
with either negative or positive group-velocity dispersion coefficients. We
demonstrate that the phase-engineered metamaterial can provide strong
group-velocity dispersion management without being adversely affected by large
transmission loss, while at the same time offering high customizability and
small footprint.Comment: 10 pages, 4 figure
Enhancing Optical Gradient Forces with Metamaterials
We demonstrate how the optical gradient force between two waveguides can be
enhanced using transformation optics. A thin layer of double-negative or
single-negative metamaterial can shrink the interwaveguide distance perceived
by light, resulting in a more than tenfold enhancement of the optical force.
This process is remarkably robust to the dissipative loss normally observed in
metamaterials. Our results provide an alternative way to boost optical gradient
forces in nanophotonic actuation systems and may be combined with existing
resonator-based enhancement methods to produce optical forces with an
unprecedented amplitude.Comment: 5 pages, 4 figures; supplemental information available from AP
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