Showing papers on "Plane wave published in 2008"
TL;DR: In this paper, an exact solution for the electromagnetic field due to an electric current in the presence of a surface conductivity model of graphene is obtained in terms of dyadic Green's functions represented as Sommerfeld integrals.
Abstract: An exact solution is obtained for the electromagnetic field due to an electric current in the presence of a surface conductivity model of graphene. The graphene is represented by an infinitesimally thin, local, and isotropic two-sided conductivity surface. The field is obtained in terms of dyadic Green’s functions represented as Sommerfeld integrals. The solution of plane wave reflection and transmission is presented, and surface wave propagation along graphene is studied via the poles of the Sommerfeld integrals. For isolated graphene characterized by complex surface conductivity σ=σ′+jσ″, a proper transverse-electric surface wave exists if and only if σ″>0 (associated with interband conductivity), and a proper transverse-magnetic surface wave exists for σ″<0 (associated with intraband conductivity). By tuning the chemical potential at infrared frequencies, the sign of σ″ can be varied, allowing for some control over surface wave properties.
2,304 citations
TL;DR: Wave front shaping is used to selectively couple light to the open transport eigenchannels, specific solutions of Maxwell's equations which the sample transmits fully, resulting in an increase in the total angle-integrated transmission compared to the case where plane waves are incident.
Abstract: We experimentally demonstrate increased diffuse transmission of light through strongly scattering materials. Wave front shaping is used to selectively couple light to the open transport eigenchannels, specific solutions of Maxwell's equations which the sample transmits fully, resulting in an increase of up to 44% in the total angle-integrated transmission compared to the case where plane waves are incident. The results for each of several hundreds of experimental runs are in excellent quantitative agreement with random matrix theory. From our measurements we conclude that with perfectly shaped wave fronts the transmission of a disordered sample tends to a universal value of 2/3, regardless of the thickness.
358 citations
TL;DR: In this paper, a supercell plane wave expansion (SC-PWE) method was proposed for the calculation of elastic band structures of two-dimensional phononic crystal plates. But the method suffers from convergence difficulties.
Abstract: We introduce a supercell plane wave expansion (SC-PWE) method for the calculation of elastic band structures of two-dimensional phononic crystal plates. We compute the band structure of solid-solid and air-solid two-dimensional phononic crystal plates. The air is modeled as a low impedance medium (LIM) with very low density and very high velocities of sound. We investigate the influence of the constituent materials, of the plate thickness, and of the geometry of the array on the band structure. We establish the range of validity of the SC-PWE method in terms of the rate of convergence with respect to the number of plane waves and contrast in physical properties of the matrix and inclusion materials. We show that for high contrast solid-solid phononic crystal plates, our SC-PWE method, as other PWE-based methods introduced to date, suffers from convergence difficulties. In the case of air (modeled as the LIM) holes-solid plates, we demonstrate that the SC-PWE method leads to fast convergence for a wide range of values of solid physical properties. With these constituent materials, we find that the largest absolute forbidden bands occur in the band structure of the phononic crystal plate provided the thickness of the plate is of the order of magnitude of the periodicity of the array of inclusions. We demonstrate the existence of guided modes in an air-silicon phononic crystal plate containing a linear defect.
248 citations
TL;DR: It is shown theoretically that a directional dipole wave can be perfectly reflected by a single pointlike oscillating dipole, and found that, in the case of a strongly focused plane wave, up to 85% of the incident light can be reflected by the dipole.
Abstract: We show theoretically that a directional dipole wave can be perfectly reflected by a single pointlike oscillating dipole Furthermore, we find that, in the case of a strongly focused plane wave, up to 85% of the incident light can be reflected by the dipole Our results hold for the full spectrum of the electromagnetic interactions and have immediate implications for achieving strong coupling between a single propagating photon and a single quantum emitter
198 citations
TL;DR: In this paper, the Landau-Lifshitz form of the Lorentz-Abraham-Dirac equation in the presence of a plane wave of arbitrary shape and polarization is solved exactly and in closed form.
Abstract: The Landau–Lifshitz (The Classical Theory of Fields. Elsevier, Oxford 1975) form of the Lorentz–Abraham–Dirac equation in the presence of a plane wave of arbitrary shape and polarization is solved exactly and in closed form. The explicit solution is presented in the particular, paradigmatic cases of a constant crossed field and of a monochromatic wave with circular and with linear polarization.
177 citations
TL;DR: In this article, the authors proposed an almost costless scheme, which allows us to divide the number of empty states by about a factor of 5 to reach the same accuracy, accelerating all calculations from small primitive cells to large supercells.
Abstract: The GW approximation to the electronic self-energy yields band structures in excellent agreement with experimental data. Unfortunately, this type of calculation is extremely cumbersome even for present-day computers. The huge number of empty states required both in the calculation of the polarizability and of the self-energy is a major bottleneck in GW calculations. We propose an almost costless scheme, which allows us to divide the number of empty states by about a factor of 5 to reach the same accuracy. The computational cost and the memory requirements are decreased by the same amount, accelerating all calculations from small primitive cells to large supercells.
173 citations
TL;DR: In this article, a maximally supersymmetric one-parameter deformation of the field theory action of Bagger and Lambert was shown to be invariant under the superalgebra of the Type IIB plane wave in the discrete light-cone quantization.
Abstract: We write down a maximally supersymmetric one parameter deformation of the field theory action of Bagger and Lambert. We show that this theory on RxT^2 is invariant under the superalgebra of the maximally supersymmetric Type IIB plane wave. It is argued that this theory holographically describes the Type IIB plane wave in the discrete light-cone quantization (DLCQ).
132 citations
TL;DR: A study on the algebraic Helmholtz inversion (AHI) applied to planar MRE, demonstrating that the deduced phase speed of shear waves depends strongly on the relative orientations of actuator polarization, motion encoding direction and image plane as well as on the actuator plate size, signal-to-noise ratio and discretization of the wave image.
Abstract: Magnetic resonance elastography (MRE) is an increasingly used noninvasive modality for diagnosing diseases using the response of soft tissue to harmonic shear waves. We present a study on the algebraic Helmholtz inversion (AHI) applied to planar MRE, demonstrating that the deduced phase speed of shear waves depends strongly on the relative orientations of actuator polarization, motion encoding direction and image plane as well as on the actuator plate size, signal-to-noise ratio and discretization of the wave image. Results from the numerical calculation of harmonic elastic waves due to different excitation directions and simulated plate sizes are compared to experiments on a gel phantom. The results suggest that correct phase speed can be obtained despite these largely uncontrollable influences, if AHI is based on out-of-plane displacements and the actuator is driven at an optimal frequency yielding an optimal pixel per wavelength resolution in the wave image. Assuming plane waves, the required number of pixels per wavelength depends only on the degree of noise.
127 citations
TL;DR: In this article, a nonperturbative definition of the super Yang-Mills (SYM) theory was proposed, which preserves 16 supersymmetries and the gauge symmetry.
Abstract: We propose a nonperturbative definition of $\mathcal{N}=4$ super Yang-Mills (SYM). We realize $\mathcal{N}=4$ SYM on $R\ifmmode\times\else\texttimes\fi{}{S}^{3}$ as the theory around a vacuum of the plane wave matrix model. Our regularization preserves 16 supersymmetries and the gauge symmetry. We perform the 1-loop calculation to give evidences that the superconformal symmetry is restored in the continuum limit.
123 citations
TL;DR: In this paper, the authors investigated the conversion from cylindrical waves to plane waves in a short range through a metamaterial layer which has a circular shape in the inner outline and a square shape in outer outline.
Abstract: We investigate the conversion from cylindrical waves to plane waves in a short range through a metamaterial layer which has a circular shape in the inner outline and a square shape in the outer outline. Based on an embedded optical transformation, analytical formulas of the permittivity and permeability tensors are presented for the metamaterial layer which converts the cylindrical waves to plane waves. The designed conversion materials are validated by full-wave simulations using the finite-element method. The proposed structure can be used either as a four-beam antenna or a compact range for near-field measurement of plane waves.
120 citations
TL;DR: In this article, a near-field far-field transformation algorithm employing plane wave expansion is presented and applied to the case of spherical near field measurements, which exploits the benefits of diagonalized translation operators, known from fast multipole methods.
Abstract: Near-field antenna measurements combined with a near-field far-field transformation are an established antenna characterization technique. The approach avoids far-field measurements and offers a wide area of post-processing possibilities including radiation pattern determination and diagnostic methods. In this paper, a near-field far-field transformation algorithm employing plane wave expansion is presented and applied to the case of spherical near-field measurements. Compared to existing algorithms, this approach exploits the benefits of diagonalized translation operators, known from fast multipole methods. Due to the plane wave based field representation, a probe correction, using directly the probe's far-field pattern can easily be integrated into the transformation. Hence, it is possible to perform a full probe correction for arbitrary field probes with almost no additional effort. In contrast to other plane wave techniques, like holographic projections, which are suitable for highly directive antennas, the presented approach is applicable for arbitrary radiating structures. Major advantages are low computational effort with respect to the coupling matrix elements owing to the use of diagonalized translation operators and the efficient correction of arbitrary field probes. Also, irregular measurement grids can be handled with little additional effort.
TL;DR: In this article, the full frequency dependence of the refractive index using world-line sigma model techniques together with the Penrose plane wave limit of spacetime in the neighbourhood of a null geodesic is calculated.
TL;DR: In this paper, the 1s core-level excited spectra in LiF, BeO, cubic BN, CaB6, MgB2, SiC, diamond, and C3N4 were calculated using an ab initio pseudopotential plane wave method and a projector augmented wave reconstruction.
Abstract: The 1s core-level excited spectra in LiF, BeO, cubic BN, CaB6, MgB2, SiC, diamond, and C3N4 were calculated using an ab initio pseudopotential plane wave method and a projector augmented wave reconstruction. Core-hole effects were investigated through a detailed examination of spectral differences between theoretical results from standard ground state calculations and from supercell calculations that included the core hole. A quantitative analysis reveals a relationship between core-hole strength and the valence charge population.
TL;DR: In this article, the Casimir energy is computed in the geometry of interest for the most precise experiments, a plane and a sphere in electromagnetic vacuum, and the scattering formula is developed on adapted plane waves and multipole basis, leading to an expression valid for arbitrary relative values of the sphere radius and interplate distance.
Abstract: The Casimir energy is computed in the geometry of interest for the most precise experiments, a plane and a sphere in electromagnetic vacuum. The scattering formula is developed on adapted plane waves and multipole basis, leading to an expression valid for arbitrary relative values of the sphere radius and interplate distance. In the limiting case of perfect reflection, the electromagnetic result is found to depart from the commonly used proximity-force approximation (PFA) significantly more rapidly than expected from scalar computations.
TL;DR: In this article, a conversional three-dimensional plane wave expansion method was revised to investigate the lamb wave propagation in the plate with two-dimensional phononic crystal layer coated on uniform substrate.
TL;DR: In this paper, the optical effects occurring during the interaction of light with dielectric gratings and explain how they can be exploited to enhance light absorption in thin-film solar cells.
Abstract: We study numerically in detail optical effects occurring during the interaction of light with dielectric gratings and explain how they can be exploited to enhance light absorption in thin-film solar cells. We analyze in depth two scenarios with practical relevance where dielectric gratings are incorporated. The first is an one-dimensional, binary grating, which can be manufactured lithographically. The second is a two-dimensional grating of dielectric spheres that can be fabricated employing self organization processes on pre-textured substrates. From a universally valid point of view, we finally outline strategies to optimize the geometry of textured surfaces permitting for a maximization of absorption in a solar cell. Absorption enhancement in a solar cell due to the presence of a grating. The right picture shows the electric field distribution if a plane wave illuminates this grating.
TL;DR: In this article, a new model of the equations of generalized thermovisco-elasticity for a thermally, isotropic and electrically conducting half-space solid whose surface is subjected to a thermal shock is given.
TL;DR: Exper experimentally recorded intensity profiles are in good agreement with the theoretically expected profiles of Laguerre-Gauss vortex beams.
Abstract: Laguerre-Gauss vortex beams carrying different topological charges are generated from Hermite-Gauss laser beams emitted by a gas laser, and their phase properties are explored by studying their interference with a plane wave. Interference of two Laguerre-Gauss vortex beams carrying equal but opposite topological charge is also studied by using a modified Mach-Zehnder interferometer. Experimentally recorded intensity profiles are in good agreement with the theoretically expected profiles.
TL;DR: In this article, an analytical solution for the electromagnetic scattering from a perfect electromagnetic conducting circular cylinder, embedded in the dielectric half-space, was presented, which utilizes the spectral (plane wave) representations of the fields and accounts for all the multiple interactions between the buried circular cylinder and the interface separating the two half spaces.
Abstract: An analytical solution is presented for the electromagnetic scattering from a perfect electromagnetic conducting circular cylinder, embedded in the dielectric half-space. The solution utilizes the spectral (plane wave) representations of the fields and accounts for all the multiple interactions between the buried circular cylinder and the dielectric interface separating the two half spaces.
TL;DR: In this article, the authors exploit a previous computation of the self-mass-squared from quantum gravity to include quantum corrections to the scalar evolution equation and show that the plane wave mode functions are shown to receive no significant one loop corrections at late times.
Abstract: We exploit a previous computation of the self-mass-squared from quantum gravity to include quantum corrections to the scalar evolution equation. The plane wave mode functions are shown to receive no significant one loop corrections at late times. This result probably applies as well to the inflaton of scalar-driven inflation. If so, there is no significant correction to the {phi}{phi} correlator that plays a crucial role in computations of the power spectrum.
Journal Article•
TL;DR: In this article, the nonlinear Klein-Gordon equation was discussed and the traveling wave solutions were derived by applying trigonometric function series method and they are complex linear combinations of kink solitary wave solutions and bell solitary wave solution.
Abstract: In this paper we discuss the nonlinear Klein-Gordon equation and we derive the new traveling wave solutions by applying trigonometric function series method. Also, they are complex linear combinations of kink solitary wave solutions and bell solitary wave solutions.
TL;DR: In this paper, the absorbance, reflectance, and transmittance of a linearly polarized, obliquely incident plane wave were calculated for a planar metal/SNTF interface in the Kretschmann configuration, the wave vector of the plane wave lying wholly in the morphologically significant plane of the SNTF.
Abstract: A sculptured nematic thin film (SNTF) is an assembly of parallel nanowires that are shaped in a fixed plane orthogonal to the substrate on which the film is deposited. The absorbance, reflectance, and transmittance of a linearly polarized, obliquely incident plane wave were calculated for a planar metal/SNTF interface in the Kretschmann configuration, the wave vector of the plane wave lying wholly in the morphologically significant plane of the SNTF. The permittivity profile of the chosen SNTF was supposed to have been sculptured during physical vapor deposition by varying the vapor incidence angle sinusoidally about a mean value. Calculations revealed that (i) multiple surface-plasmon-polariton (SPP) trains of the same color can be independently guided by the metal/SNTF interface, (ii) not all SPP trains have to be co-propagating, and (iii) not all SPP trains have to be of the same linear polarization state. As different SPP trains move with different speeds, guided by the interface, exciting prospects emerge for error-free sensing and plasmonics-based communication.
TL;DR: In this paper, a model for guided wave scattering from non-symmetric blind holes in isotropic plates using Poisson and Mindlin plate wave theories for in-plane and flexural wave modes, respectively, is presented.
TL;DR: In this article, an approximate analysis based on a homogenized model for the wire medium as well as a rigorous full-wave analysis of the actual periodic structure of a grounded wire medium slab excited by a simple canonical source is presented.
Abstract: Radiation features are studied for a grounded wire-medium slab excited by a simple canonical source, i.e., a horizontal electric dipole. For the first time, an approximate analysis based on a homogenized model for the wire medium as well as a rigorous full-wave analysis of the actual periodic structure are presented. The homogeneous model takes into account both anisotropy and spatial dispersion of the metamaterial medium in the long-wavelength regime. One rather surprising result is that this structure allows for directive pencil beams at broadside that are azimuthally symmetric (in spite of the directionality of the wires). The structure also allows for conical beams that point at a chosen scan angle, where the beam angle and beamwidth are azimuthally independent, and the beam peak in the elevation planes remains approximately constant during the scanning process, in contrast with other types of planar leaky-wave antennas. These remarkable features are explained in terms of the azimuthal independence of the wavenumber for the leaky mode that is responsible for the beam.
TL;DR: In this paper, a maximally supersymmetric one parameter deformation of the field theory action of Bagger and Lambert was shown to be invariant under the superalgebra of the maximally superymmetric Type IIB plane wave in the discrete light-cone quantization.
Abstract: We write down a maximally supersymmetric one parameter deformation of the field theory action of Bagger and Lambert. We show that this theory on R ? T2 is invariant under the superalgebra of the maximally supersymmetric Type IIB plane wave. It is argued that this theory holographically describes the Type IIB plane wave in the discrete light-cone quantization (DLCQ).
TL;DR: In this paper, the authors derived the exact acoustic scattering from a sphere immersed in an ideal fluid and centered along the propagation axis of a standing or quasi-standing zero-order Bessel beam, and explicit partial-wave representations for the radiation force were derived.
TL;DR: In this article, a metamaterial particle which is composed of a dielectric block with a thin metallic rod screwed inside is proposed to control the effective medium parameters of a periodic structure composed of the particles.
Abstract: We propose a metamaterial particle which is composed of a dielectric block with a thin metallic rod screwed inside. By adjusting the height of rod inside the dielectric block, we can control the effective medium parameters of a periodic structure composed of the particles. An experiment is presented to retrieve the effective medium parameters, which have good agreements with those from simulation results. Using the unique property of the tunable particles, gradient metamaterial lenses are easily designed to deflect and focus the incident plane waves.
TL;DR: The important role of the bridging oxygen in the H 2O dissociation process is discussed and the influence of the second layer of H2O molecules on relaxation of the surface atoms was estimated.
Abstract: Mono- and bilayer adsorption of H2O molecules on TiO2 and SnO2 (110) surfaces has been investigated using static planewave density functional theory (PW DFT) simulations. Potential energies and structures were calculated for the associative, mixed, and dissociative adsorption states. The DOS of the bare and hydrated surfaces has been used for the analysis of the difference between the H2O interaction with TiO2 and SnO2 surfaces. The important role of the bridging oxygen in the H2O dissociation process is discussed. The influence of the second layer of H2O molecules on relaxation of the surface atoms was estimated.
TL;DR: In this paper, a perfect electromagnetic conductor (PEMC) circular cylinder, coated with a metamaterial, was investigated theoretically, and the analysis was carried out in parallel and perpendicular polarization cases.
TL;DR: In this article, the authors interpreted the vertical profiles of horizontal velocity obtained during the Mid-Ocean Dynamics Experiment (MODE) as being representative of the background internal wave field, and thus, despite some evidence of excess downward energy propagation associated with coherent near-inertial features that was interpreted in terms of atmospheric generation, these data provided the basis for a revision to the Garrett and Munk spectral model.
Abstract: Vertical profiles of horizontal velocity obtained during the Mid-Ocean Dynamics Experiment (MODE) provided the first published estimates of the high vertical wavenumber structure of horizontal velocity. The data were interpreted as being representative of the background internal wave field, and thus, despite some evidence of excess downward energy propagation associated with coherent near-inertial features that was interpreted in terms of atmospheric generation, these data provided the basis for a revision to the Garrett and Munk spectral model. These data are reinterpreted through the lens of 30 years of research. Rather than representing the background wave field, atmospheric generation, or even near-inertial wave trapping, the coherent high wavenumber features are characteristic of internal wave capture in a mesoscale strain field. Wave capture represents a generalization of critical layer events for flows lacking the spatial symmetry inherent in a parallel shear flow or isolated vortex.