Impossibility of Smooth Negative Refraction (original) (raw)

Negative refraction of low-frequency electromagnetic waves

physica status solidi (RRL) - Rapid Research Letters, 2008

Since the first experimental observation of negative refraction in a narrow microwave frequency region [1], a great effort has been made to enhance operating frequencies in the near-infrared and visible ranges of the spectrum . A large number of papers are now available concerning the different properties and possible applications of negative index metamaterials (see, for example and citations therein). Most of suggested metamaterials are complex to manufacture, incur large optical losses and require overlapping double-resonance properties for securing simultaneously negative permittivity and permeability. More recently, an all-semiconductor heavily doped three-dimensional metamaterial has been demonstrated which exhibits negative refraction in the long-infrared region and requires only an anisotropic dielectric permittivity with a single resonance . Such a possibility in certain classes of uniaxially anisotropic media has been predicted theoretically .

Electromagnetic Wave Propagation in Media with Indefinite Permittivity and Permeability Tensors

2002

We study the behavior of wave propagation in materials for which not all of the principal elements of the permeability and permittivity tensors have the same sign. We find that a wide variety of effects can be realized in such media, including negative refraction, near-field focusing, and high impedance surface reflection. In particular, a bilayer of these materials can transfer a field distribution from one side to the other, including near fields, without requiring internal exponentially growing waves.

Negative refraction in indefinite media

Journal of The Optical Society of America B-optical Physics, 2004

Initial experiments on wedge samples composed of isotropic metamaterials with simultaneously negative permittivity and permeability have indicated that electromagnetic radiation can be negatively refracted. In more recently reported experiments [Phys. Rev. Lett. 90, 1074011 (2003)], indefinite metamaterial samples, for which the permittivity and permeability tensors are negative along only certain of the principal axes of the metamaterial, have also been used to demonstrate negative refraction. We present here a detailed analysis of the refraction and reflection behavior of electromagnetic waves at an interface between an indefinite medium and vacuum. We conclude that certain classes of indefinite media have identical refractive properties as isotropic negative index materials. However, there are limits to this correspondence, and other complicating phenomena may occur when indefinite media are substituted for isotropic negative index materials. We illustrate the results of our analysis with finite-element-based numerical simulations on planar slabs and wedges of negative index and indefinite media.

Linear and nonlinear wave propagation in negative refraction metamaterials

Physical Review B, 2004

We discuss linear and nonlinear optical wave propagation in a left-handed medium (LHM) or medium of negative refraction (NRM). We use the approach of characterizing the medium response totally by a generalized electric polarization (with a dielectric permittivity ) that can be decomposed into a curl and a non-curl part. The description has a one-to-one correspondence with the usual approach characterizing the LHM response with a dielectric permittivity ε<0 and a magnetic permeability μ<0. The latter approach is less physically transparent in the optical frequency region because the usual definition of magnetization loses its physical meaning. Linear wave propagation in LHM or NRM is characterized by negative refraction and negative group velocity that could be clearly manifested by ultra-short pulse propagation in such a medium. Nonlinear optical effects in LHM can be predicted from the same calculations adopted for ordinary media using our general approach.

Wave Refraction in Negative-Index Media: Always Positive and Very Inhomogeneous

Physical Review Letters, 2002

We present the first treatment of the refraction of physical electromagnetic waves in newly developed negative index media (NIM), also known as left-handed media (LHM). The NIM dispersion relation implies that group fronts refract positively even when phase fronts refract negatively. This difference results in rapidly dispersing, very inhomogeneous waves. In fact, causality and finite signal speed always prevent negative wave signal (not phase) refraction. Earlier interpretations of phase refraction as "negative light refraction" and "light focusing by plane slabs" are therefore incorrect, and published NIM experiments can be explained without invoking negative signal refraction.

The negative index of refraction demystified

European Journal of Physics, 2002

We study electromagnetic wave propagation in mediums in which the effective relative permittivity and the effective relative permeability are allowed to take any value in the upper half of the complex plane. A general condition is derived for the phase velocity to be oppositely directed to the power flow. That extends the recently studied case of propagation in mediums for which the relative permittivity and relative permeability are both simultaneously negative, to include dissipation as well. An illustrative case study demonstrates that in general the spectrum divides into five distinct regions.

Electromagnetic Wave Propagation Through Single Negative Index Material

Journal of Ovonic …, 2010

Due to the potential applications of a negative index material (NIM), the development of the NIM has been occurred at an outstanding place in optics. To understand the optical properties of the single NIM layer, we have studied the propagation of electromagnetic wave through a medium of single NIM layer which is sandwiched between two dielectric materials. By using simple translational matrix method, the optical properties of the structure have calculated in the effect of thickness and plasma frequency of the NIM layer. The zero-refractive index, transmittance and dispersion of the structure are controlled by the thickness and the separation between the electric and magnetic plasma frequencies of NIM layer. The study of the electromagnetic wave propagation through the single negative index material may help to study the unusual behavior of the periodic structure containing NIMs. The study reveals that the single NIM layer can be used to make controlled optical devices (like Omni-directional reflectors) by adjusting the separation between the electric and magnetic plasma frequencies as well as the thickness of the NIM.

Propagation of a localized wavepacket in a metamaterial with a negative index of refraction

Journal of Applied Spectroscopy, 2008

Propagation properties of electromagnetic waves in a medium with a negative index of refraction are investigated. A model of a physical signal that combines simultaneously qualities of both a spatially-localized beam and a wavepacket was used as the incident wave. Such a choice was necessary because of the strong frequency dispersion of metamaterials in the spectral region with a negative index of refraction. An approximate analytical solution was derived that describes the propagation dynamics of such a signal through a slab made of material showing simultaneously a negative dielectric permittivity and magnetic permeability.

Direct evidence of negative refraction at media with negative and

Journal of Optics A: Pure and Applied Optics, 2003

We analyse wave scattering by an interface between a positive refractive index medium and a medium for which both the permittivity and the permeability are negative. We show that the negative refraction effect can be deduced directly from Maxwell equations, without references to causality or losses.

On reflection from a half-space with negative real permittivity and permeability

Microwave and Optical Technology Letters, 2002

The reflection of a normally incident wideband pulse by a halfspace whose permittivity and permeability obey the one-resonance Lorentz model is calculated. The results are compared with those from frequency-domain reflection analysis. In the spectral regime wherein the real parts of the permittivity and the permeability are negative, as well as in small adjacent neighborhoods of that regime, the time-domain analysis validates the conclusion that it is sufficient to ensure that the imaginary part of the refractive index is positive-regardless of the sign of the real part of the refractive index.