7,218 research outputs found

    Negative effective permeability and left-handed materials at optical frequencies

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    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

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    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

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    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 nˉ\bar{n} 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

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    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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