631 research outputs found
Excitation of guided waves in layered structures with negative refraction
We study the electromagnetic beam reflection from layered structures that
include the so-called double-negative materials, also called left-handed
metamaterials. We predict that such structures can demonstrate a giant lateral
Goos-Hanchen shift of the scattered beam accompanied by splitting of the
reflected and transmitted beams due to the resonant excitation of surface waves
at the interfaces between the conventional and double-negative materials as
well as due to excitation of leaky modes in the layered structures. The beam
shift can be either positive or negative, depending on the type of the guided
waves excited by the incoming beam. We also perform finite-difference
time-domain simulations and confirm the major effects predicted analytically.Comment: 13 pqages, 10 figures. Also available at
http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-2-48
Nonlinear guided waves and symmetry breaking in left-handed waveguides
We analyze nonlinear guided waves in a planar waveguide made of a left-handed
material surrounded by a Kerr-like nonlinear dielectric. We predict that such a
waveguide can support fast and slow symmetric and antisymmetric nonlinear
modes. We study the symmetry breaking bifurcation and asymmetric modes in such
a symmetric structure. We analyze nonlinear dispersion properties of the guided
waves, and show that the modes can be both forward and backward.Comment: 4 pages, 3 figure
The Zero-n Gap Soliton
Periodic structures consisting of alternating layers of positive index and
negative index materials possess a novel band gap at the frequency at which the
average refractive index is zero. We show that in the presence of a Kerr
nonlinearity, this zero-n gap can switch from low transmission to a perfectly
transmitting state, forming a nonlinear resonance or gap soliton in the
process. This zero-n gap soliton is omnidirectional in contrast to the usual
Bragg gap soliton of positive index periodic structure
Multistability in nonlinear left-handed transmission lines
Employing a nonlinear left-handed transmission line as a model system, we
demonstrate experimentally the multi-stability phenomena predicted
theoretically for microstructured left-handed metamaterials with a nonlinear
response. We show that the bistability is associated with the period doubling
which at higher power may result in chaotic dynamics of the transmission line
Enhanced parametric processes in binary metamaterials
We suggest double-resonant (binary) metamaterials composed of two types of
magnetic resonant elements, and demonstrate that in the nonlinear regime such
metamaterials provide unique possibilities for phase-matched parametric
interaction and enhanced second-harmonic generation
Tunable transmission and harmonic generation in nonlinear metamaterials
We study the properties of a tunable nonlinear metamaterial operating at
microwave frequencies. We fabricate the nonlinear metamaterial composed of
double split-ring resonators and wires where a varactor diode is introduced
into each resonator so that the magnetic resonance can be tuned dynamically by
varying the input power. We show that at higher powers the transmission of the
metamaterial becomes power dependent, and we demonstrate experimentally
power-dependent transmission properties and selective generation of higher
harmonics.Comment: 3 page
Effect of microscopic disorder on magnetic properties of metamaterials
We analyze the effect of microscopic disorder on the macroscopic properties of composite metamaterials and study how weak statistically independent fluctuations of the parameters of the structure elements can modify their collective magnetic response and left-handed properties. We demonstrate that even a weak microscopic disorder may lead to a substantial modification of the metamaterial magnetic properties, and a 10% deviation in the parameters of the microscopic resonant elements may lead to a substantial suppression of the wave propagation in a wide frequency range. A noticeable suppression occurs also if more than 10% of the resonant magnetic elements possess strongly different properties, and in the latter case the defects can create an additional weak resonant line. These results are of a key importance for characterizing and optimizing novel composite metamaterials with the left-handed properties at terahertz and optical frequencies
Tamm states in one dimensional photonic crystals containing left-handed materials
We present a theoretical study of electromagnetic surface waves localized at
an interface separating a conventional uniform medium and a semi-infinite 1-D
photonic crystal made of alternate left-handed metamaterial and right-handed
material which we refer to as left-handed photonic crystal. We find novel type
of surface mode's structure, the so-called surface Tamm states and demonstrate
that the presence of metamaterial in the photonic crystal structure allows for
a flexible control of the dispersion properties of surface states, and can
support the Tamm states with a backward energy flow and a vortex-like
structure.Comment: 8pages, 5 figure
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