128 research outputs found
Transmission properties of left-handed band-gap structures
We analyze transmission of electromagnetic waves through a periodic band-gap
structure consisting of slabs of a left-handed metamaterial and air. Using the
effective parameters of the metamaterial derived from its microscopic
structure, we study, with the help of the transfer-matrix approach and by means
of the finite-difference-time-domain numerical simulations, the transmission
properties of such a left-handed photonic crystals in a novel type of band gap
associated with the zero averaged refractive index. We demonstrate that the
transmission can be made tunable by introducing defects, which allow to access
selectively two different types of band gaps.Comment: 5 pages, 8 figure
Subwavelength imaging with opaque left-handed nonlinear lens
We introduce the concept of subwavelength imaging with an opaque nonlinear
left-handed lens by generating the second-harmonic field. We consider a slab of
composite left-handed metamaterial with quadratic nonlinear response and show
that such a flat lens can form, under certain conditions, an image of the
second-harmonic field of the source being opaque at the fundamental frequency.Comment: 3 pages, 3 figure
Birefringent left-handed metamaterials and perfect lenses
We describe the properties of birefringent left-handed metamaterials and
introduce the concept of a birefringent perfect lens. We demonstrate that, in a
sharp contrast to the conventional left-handed perfect lens at
, where is the dielectric constant and is the
magnetic permeability, the birefringent left-handed lens can focus either TE or
TM polarized waves or both of them, allowing a spatial separation of the TE and
TM images. We discuss several applications of the birefringent left-handed
lenses such as the beam splitting and near-field diagnostics at the
sub-wavelength scale.Comment: 4 pages 6 figure
Second-harmonic generation in nonlinear left-handed metamaterials
We study the second-harmonic generation in left-handed metamaterials with a
quadratic nonlinear response. We demonstrate a novel type of the exact phase
matching between the backward propagating wave of the fundamental frequency and
the forward propagating wave of the second harmonics. We show that this novel
parametric process can convert a surface of the left-handed metamaterial into
an effective mirror totally reflecting the second harmonics generated by an
incident wave. We derive and analyze theoretically the coupled-mode equations
for a semi-infinite nonlinear metamaterial. We also study numerically the
second-harmonic generation by a metamaterial slab of a finite thickness, and
reveal the existence of multistable nonlinear effects.Comment: 6 pages, 6 figure
Morphology of ceramic particles produced by plasma-chemical synthesis
Thermal and diffusion processes in the droplet weakly concentrated metal salt solution during its heating in the plasma chemical reactor, in order to synthesize metal oxide powders are considered. Numerical study is based on previously proposed physical-mathematical model. The results of numerical calculations are analyzed to assess the possible influence of the operation parameters of the reactor and the characteristics of the initial solution (precursor) on the morphology of the particles formed
Nonlinear magnetoinductive waves and domain walls in composite metamaterials
We describe novel physics of nonlinear magnetoinductive waves in left-handed
composite metamaterials. We derive the coupled equations for describing the
propagation of magnetoinductive waves, and show that in the nonlinear regime
the magnetic response of a metamaterial may become bistable. We analyze
modulational instability of different nonlinear states, and also demonstrate
that nonlinear metamaterials may support the propagation of domain walls
(kinks) connecting the regions with the positive and negative magnetization.Comment: 5 pages, 5 figure
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