Enhanced diffraction by a rectangular grating made of a negative phase--velocity (or negative index) material

The diffraction of electromagnetic plane waves by a rectangular grating formed by discrete steps in the interface of a homogeneous, isotropic, linear, negative phase--velocity (negative index) material with free space is studied using the semi--analytic C method. When a nonspecular diffracted order is of the propagating type, coupling to that order is significantly larger for a negative index material than for conventional material. The computed coupling strengths reported here are in agreement with recent experiments, and illustrate the role of evanescent fields localized at the grating interface in producing this enhanced coupling.Comment: 12 pages, 4 figure

A new condition to identify isotropic dielectric-magnetic materials displaying negative phase velocity

The derivation of a new condition for characterizing isotropic dielectric-magnetic materials exhibiting negative phase velocity, and the equivalence of that condition with previously derived conditions, are presented.Comment: 4 page

On the inapplicability of a negative-phase-velocity condition as a negative-refraction condition for active materials

A negative-phase-velocity condition derived by Depine and Lakhtakia [Microwave Opt Technol Lett 41 (2004) 315] for isotropic, homogeneous, passive, dielectric-magnetic materials is inapplicable as a negative-refraction condition for active materials.Comment: replacement for preliminary version submitted earlier by erro

Tunable plasmonic enhancement of light scattering and absorption in graphene-coated subwavelength wires

The electromagnetic response of subwavelength wires coated with a graphene monolayer illuminated by a linearly polarized plane waves is investigated. The results show that the scattering and extintion cross-sections of the coated wire can be dramatically enhanced when the incident radiation resonantly excites localized surface plasmons. The enhancements occur for p--polarized incident waves and for excitation frequencies that correspond to complex poles in the coefficients of the multipole expansion for the scattered field. By dynamically tuning the chemical potential of graphene, the spectral position of the enhancements can be chosen over a wide range.Comment: Accepted for publication in Journal of Optics 201

¿Se pueden explicar y modificar las diferencias en la calidad de vida percibida, entre pacientes incidentes y prevalentes en tratamiento de diálisis?

En la literatura médica, con frecuencia, se encuentran publicaciones que hacen referencia a la calidad de vida de los pacientes en diálisis. Sin embargo, no es habitual hallar un trabajo que demuestre, con fortaleza estadística, la diferencia en la percepción de la calidad de vida entre los pacientes incidentes, que están cursando los primeros tres meses de su tratamiento hemodialítico, y prevalentes, que han superado este plazo, en muchos casos con periodos prolongados. Esta diferencia, precisamente, se ha logrado demostrar en el esclarecedor artículo producido por Varela y colegas, titulado “Calidad de vida en pacientes incidentes vs prevalentes. ¿Hay diferencia en la calidad de vida?”

Classification of dispersion equations for homogeneous dielectric-magnetic uniaxial materials

The geometric representation at a fixed frequency of the wavevector (or dispersion) surface $\omega(\vec k)$ for lossless, homogeneous dielectric--magnetic uniaxial materials is explored, when the elements of the relative permittivity and permeability tensors of the material can have any sign. Electromagnetic plane waves propagating inside the material can exhibit dispersion surfaces in the form of ellipsoids of revolution, hyperboloids of one sheet, or hyperboloids of two sheets. Furthermore, depending on the relative orientation of the optic axis, the intersections of these surfaces with fixed planes of propagation can be circles, ellipses, hyperbolas, or straight lines. The obtained understanding is used to study the reflection and refraction of electromagnetic plane waves due to a planar interface with an isotropic medium

Alien Registration- Cameron, Sarah (Bath, Sagadahoc County)

https://digitalmaine.com/alien_docs/9573/thumbnail.jp

Negative refraction in active and passive media: a discussion of various criteria

There are three widely-used conditions for characterizing negative refraction in isotropic dielectric-magnetic materials. Here we demonstrate that whilst all the different conditions are equivalent for purely passive media, they are distinct if active media are considered. Further, these criteria can also be applied to negative refraction in acoustic materials, where we might replace the dielectric permittivity $\epsilon$ with a bulk modulus $\kappa$, and the magnetic permeability $\mu$ with the mass density $\rho$.Comment: 3 pages, 4 figures; a revised version of the paper Microwave Opt. Tech. Lett. 50, 1804 (2008). Acoustics comments added 201