7,218 research outputs found
Negative effective permeability and left-handed materials at optical frequencies
We present here the design of nano-inclusions made of properly arranged
collections of plasmonic metallic nano-particles that may exhibit a resonant
magnetic dipole collective response in the visible domain. When such inclusions
are embedded in a host medium, they may provide metamaterials with negative
effective permeability at optical frequencies. We also show how the same
inclusions may provide resonant electric dipole response and, when combining
the two effects at the same frequencies, lefthanded materials with both
negative effective permittivity and permeability may be synthesized in the
optical domain with potential applications for imaging and nano-optics
applications.Comment: 11 pages, 6 figures; modified the format, added a figur
Negative Refraction and Left-handed electromagnetism in Microwave Photonic Crystals
We demonstrate negative refraction of microwaves in metallic photonic
crystals. The spectral response of the photonic crystal, which manifests both
positive and negative refraction, is in complete agreement with band-structure
calculations and numerical simulations. The negative refraction observed
corresponds to left-handed electromagnetism and arises due to the dispersion
characteristics of waves in a periodic medium. This mechanism for negative
refraction is different from that in metamaterials.Comment: 13 pages, 4 figure
Surface polaritons in two-dimensional left-handed photonic crystals
Using an extended plane-wave-based transfer-matrix method, the photonic band
structures and the corresponding transmission spectrum of a two-dimensional
left-handed photonic crystal are calculated. Comparisons between the periodic
structure with a single left-handed cylindric rod are made, and many
interesting similarities are found. It is shown that, due to the localized
surface polaritons presented by an isolated left-handed rod, there exist many
exciting physical phenomena in high-dimensional left-handed photonic crystals.
As direct results of coupling of the localized surface polaritons of
neighboring left-handed rod, a lot of almost dispersionless bands,
anti-crossing behavior, and a zero gap are exhibited in the
left-handed periodic structure. Moreover, in a certain frequency region, except
distorted by a lot of anti-crossing behavior, there exists a continual
dispersion relation, which can be explained by the long-wavelength
approximation. It is also pointed out that high-dimensional left-handed
photonic crystals can be used to design narrow-band filter.Comment: sign errors in equation
Subwavelength imaging with opaque left-handed nonlinear lens
We introduce the concept of subwavelength imaging with an opaque nonlinear
left-handed lens by generating the second-harmonic field. We consider a slab of
composite left-handed metamaterial with quadratic nonlinear response and show
that such a flat lens can form, under certain conditions, an image of the
second-harmonic field of the source being opaque at the fundamental frequency.Comment: 3 pages, 3 figure
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