80 research outputs found
Symmetry and reciprocity constraints on diffraction by gratings of quasi-planar particles
Symmetry and reciprocity constraints on polarization state of the field
diffracted by gratings of quasi-planar particles are considered. It is shown
that the optical activity effects observed recently in arrays of quasi-planar
plasmonic particles on a dielectric substrate are due to the reflection of the
field at the air-dielectric slab interface and are proportional to this
reflection coefficient.Comment: 11 pages, 3 figures, 12 references; minor corrections for better
appearanc
Design of Voltage control Oscillator using Nonlinear Composite Right/Left-Handed Transmission Line
In the present work, we propose a voltage control oscillator (VCO) at high frequency consists of nonlinear composite right/left-handed transmission line (CRLH-TL) loaded with Resonant Tunneling Diode (RTD). We designed three prototype device examples. The first one consists of one cell with short circuit at the beginning of the cell between ground and patch, and 50 Ω load resistance were added at the end of the cell between ground and patch. The second one is similar to the first prototype but with open circuit at the beginning of the cell instated of short circuit. The third prototype consists of one cell with two 50 Ω load resistances added between ground and patch at the beginning and at the end of the cell. The proposed VCO models are capable of generating oscillations at frequencies between 4.87- 14.9 GHz. In our simulations, we used OrCAD and ADS software to analyze the proposed circuit
Transformation-based spherical cloaks designed by an implicit transformation-independent method: theory and optimization
Based on the concept of the cloak generating function, we propose an implicit transformation-independent method for the required parameters of spherical cloaks without knowing the needed coordinate transformation beforehand. A non-ideal discrete model is used to calculate and optimize the total scattering cross-sections of different profiles of the generating function. A bell-shaped quadratic spherical cloak is found to be the best candidate, which is further optimized by controlling the design parameters involved. Such improved invisibility is steady even when the model is highly discretized.European Commission (European Network of Excellence 'METAMORPHOSE')Foundation for Fundamental Research (Belarus) (F08MS-06
Quantum formulation for nanoscale optical and material chirality: symmetry issues, space and time parity, and observables
To properly represent the interplay and coupling of optical and material chirality at the photon-molecule or photon-nanoparticle level invites a recognition of quantum facets in the fundamental aspects and mechanisms of light-matter interaction. It is therefore appropriate to cast theory in a general quantum form, one that is applicable to both linear and nonlinear optics as well as various forms of chiroptical interaction including chiral optomechanics. Such a framework, fully accounting for both radiation and matter in quantum terms, facilitates the scrutiny and identification of key issues concerning spatial and temporal parity, scale, dissipation and measurement. Furthermore it fully provides for describing the interactions of light beams with a vortex character, and it leads to the complete identification of symmetry conditions for materials to provide for chiral discrimination. Quantum considerations also lend a distinctive perspective to the very different senses in which other aspects of chirality are recognized in metamaterials. Duly attending to the symmetry principles governing allowed or disallowed forms of chiral discrimination supports an objective appraisal of the experimental possibilities and developing applications
Control of planar nonlinear guided waves and spatial solitons with a left-handed medium
The evidence that double negative media, with an effective negative
permittivity, and an effective negative permeability, can be manufactured to
operate at frequencies ranging from microwave to optical is ushering in a new
era of metamaterials. They are referred to here as 'left-handed', even though a
variety of names is evident from the literature. In anticipation of a demand
for highly structured integrated practical waveguides, this paper addresses the
impact of this type of medium upon waveguides that can be also nonlinear. After
an interesting historical overview and an exposure of some straightforward
concepts, a planar guide is investigated, in which the waveguide is a slab
consisting of a left-handed medium sandwiched between a substrate and cladding
that are simple dielectrics. The substrate and cladding display a Kerr-type
nonlinear response. Because of the nonlinear properties of the Kerr media, the
power flow direction can be controlled by the intensity of the electric field.
A comprehensive finite-difference-time-domain (FDTD) analysis is presented that
concentrates upon spatial soliton behaviour. An interesting soliton-lens
arrangement is investigated that lends itself to a novel cancellation effect.Comment: 19 pages, 11 figure
Shifted resonances in coated metamaterial cylinders: Enhanced backscattering and near-field effects
10.1103/PhysRevE.77.046604Physical Review E - Statistical, Nonlinear, and Soft Matter Physics774-PLEE
Isotropic non-ideal cloaks providing improved invisibility by adaptive segmentation and optimal refractive index profile from ordering isotropic materials
10.1364/OE.18.14950Optics Express181414950-1495
Penetration effect in uniaxial anisotropic metamaterials
International audiencePlane harmonic wave propagation along an interface between vacuum and a semi-infinite anisotropic metamaterial is considered. Possibility of penetration effect in the considered case is studied. It is shown that there is a bulk wave within the anisotropic metamaterial with an arbitrary orientation of the anisotropy axis. It is also proved that a reflected wave must propagate perpendicularly to the interface in the case of the extraordinary wave. Moreover, no wave is reflected in the case of ordinary wave propagation
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