1,720,969 research outputs found
Metamaterials: demonstrating toroidal moment in the frame of classical electrodynamics
No full textWe present electromagnetic metamaterials the resonant response of which cannot be attributed to the excitation of conventional magnetic or charge multipoles and can only be explained by the existence of the induced toroidal dipole
Non-trivial non-radiating excitations and ultra-narrow resonances in toroidal metamaterials
No full textWe demonstrate theoretically and confirm experimentally a new mechanism of resonant electromagnetic transparency, which yields narrow isolated symmetric Lorentzian transmission lines in metamaterials. It exploits the long sought non-trivial non-radiating charge-current excitation based on interfering electric and toroidal dipole moments
Non-radiating excitations vector potential waves and toroidal metamaterials
No full textWe report on electromagnetic metamaterials that exploit interference between electrical and toroidal dipolar modes of excitation to generate non-trivial gauge-irreducible vector potential in the absence of scattered electromagnetic fields
Non-trivial non-radiating excitations and vector potential in toroidal metamaterials
No full textWe report on electromagnetic metamaterials that exploit interference between electrical and toroidal dipolar modes of excitation to generate non-trivial gauge-irreducible vector potential in the absence of scattered electromagnetic fields
Giant gyrotropy due to electromagnetic-field coupling in a bilayered chiral structure
No full textWe report experimental evidence that electromagnetic coupling between physically separated planar metal patterns located in parallel planes provides for extremely strong polarization rotatory power if one pattern is twisted with respect to the other, creating a chiral object. In terms of a rotary power per sample thickness equal to one wavelength, the bilayered structure rotates 5 orders of magnitude stronger than a gyrotropic crystal of quartz in the visible spectrum
Giant gyrotropy in bi-layered chiral structures
No full textWe show that a layered structure consisting of two identical planar metal patterns can show exceptionally strong resonant gyrotropy if one pattern is twisted with respect to the other thus creating a 3D-chiral object. This effect is analogous to the gyrotropy of bulk media comprised of chiral molecules was and was first theoretically analyzed in [Appl. Phys. Lett. 78, 498 (2001)]. Using helicoidally arranged planar metal rosettes of 4-fold rotational symmetry we achieved enantiomerically sensitive polarization plane rotation (optical activity) of about 30 degrees and circular dichroism in the microwave part of the spectrum. The ability to create gyrotropic structures utilizing planar technology provides opportunities for manufacturing artificial gyrotropic materials, which can be use to manipulate the polarization state of radiation in the optical and microwave ranges. The range of possible applications of such structures includes computer displays and various opto-electronic devices. Its exceptionally strong gyrotropy can also be used for developing so-called negative refractive-index media wherein simultaneous electric and magnetic resonances at optical frequencies are needed to achieve negative refraction. Using appropriately scaled subwavelength nano-structures we expect to confirm this strong gyrotropy in the optical part of the spectrum
Nanostructured metal as optical magnetic wall
No full textWe report first demonstration of optical “magnetic wall”. Magnetic wall is a mirror, which in contrast to a conventional mirror, inflicts only small or zero change to the phase of a reflected wave. This intriguing and very useful property is achieved by nanostructuring of metal surface on subwavelength scale. Our experimental results are compared and well explained by numerical calculations. Among various application, which an optical magnetic wall could have, are magnificent resonant properties of harvesting light, e.g. for enhancement of photo-detector sensitivity and in polarization conversion for display applications.<br/
'Miracle' mirror that does not change the phase of reflected wave
No full textElectromagnetic wave reflected from a flat metallic mirror superimposed with a wavy structure with sub-wavelength features that resemble 'fish-scales' shows no phase change with respect to the incident wave
Asymmetric transmission of light through a planar chiral meta-material
No full textWe report the first experiential observation and theoretical analysis of the new phenomenon of planar chiral circular conversion dichroism, which in some aspects resembles the Faraday effect in magnetized media, but does not require the presence of a magnetic field for its observation. It results from the interaction of an electromagnetic wave with an anisotropic chiral planar structure patterned on the sub-wavelength scale, and manifests itself in asymmetric transmission of circularly polarized waves in the opposite directions through the structure and elliptically polarized eigenstates. The new effect is radically different from conventional gyrotropy of three-dimensional chiral media. The effect of planar chiral circular conversion dichroism has been observed both in the microwave and optical parts of the spectrum
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