150 research outputs found
Left-Handed Surface Waves in a Photonic Structure
It is demonstrated that an isotropic left-handed medium can be constructed as
a photonic structure consisting of two dielectric materials, one with positive
and another with negative dielectric permittivities epsilon. Electromagnetic
waves supported by this structure are the surface waves localized at the
dielectric interfaces. These surface waves can be either surface phonons or
surface plasmons. Two examples of negative epsilon materials are used: silicon
carbide and free-electron gas.Comment: 7 pages, two figure
Imaging Studies of Characteristics for a Slab of a Lossy Left-handed Material
The characteristics of an imaging system formed by a slab of a lossy
left-handed material (LHM) are studied. The transfer function of the LHM
imaging system is written in an appropriate product form with each term having
a clear physical interpretation. A tiny loss of the LHM may suppress the
transmission of evanescent waves through the LHM slab and this is explained
physically. An analytical expression for the resolution of the imaging system
is derived. It is shown that it is impossible to make a subwavelength imaging
by using a realistic LHM imaging system unless the LHM slab is much thinner
than the wavelength.Comment: 15 pages, 10 figure
Refraction of Electromagnetic Energy for Wave Packets Incident on a Negative Index Medium is Always Negative
We analyze refraction of electromagnetic wave packets on passing from an
isotropic positive to an isotropic negative refractive index medium. We
definitively show that in all cases the energy is always refracted negatively.
For localized wave packets, the group refraction is also always negative.Comment: 5 pages, 3 figure
Diffraction theory and focusing of light by left-handed materials
A diffraction theory in a system consisting of left-handed and right-handed
materials is proposed. The theory is based upon the Huygens's principle and the
Kirchhoff's integral and it is valid if the wavelength is smaller than any
relevant length of the system. The theory is applied to the calculation of the
smearing of the foci of the Veselago lens due to the finite wavelength. We show
that the Veselago lens is a unique optical instrument for the 3D imaging, but
it is not a ``superlens'' as it has been claimed recently.Comment: 7 pages, 2 figure
Amphoteric refraction at the interface between isotropic and anisotropic media
It is found that the amphoteric refraction, i.e. the refraction can be either
positive or negative depending on the incident angles, could occur at a planar
interface associated with a uniaxially anisotropic positive index media (PIM)
or an anisotropic negative index media (NIM). Particularly, the anomalous
negative refraction can occur at a planar interface from an isotropic PIM to an
anisotropic PIM, whereas the anomalous positive refraction occurs at the
interface from an isotropic PIM to an anisotropic NIM. The optimal conditions
to yield the two unusual refractions are obtained. The difference of the two
types of amphoteric refraction is discussed.Comment: 12 pages, 5 figure
Resolving the wave-vector in negative refractive media: The sign of
We address the general issue of resolving the wave-vector in complex
electromagnetic media including negative refractive media. This requires us to
make a physical choice for the sign of a square-root imposed merely by
conditions of causality. By considering the analytic behaviour of the
wave-vector in the complex plane, it is shown that there are a total of eight
physically distinct cases in the four quadrants of two Riemann sheets.Comment: 3 pages, 2 figures, RevTe
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