We 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 a planar chiral 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.Since Hetch and Barron [1] and Arnaut and Davis [2] first introduced planar chiral structures to electromagnetic research they have become the subject of intense theoretical [3,4] and experimental investigations with respect to the polarization properties of scattered fields [5,6,7]. It was understood by many that planar chirality is essentially different in symmetry from threedimensional chirality. Whereas in three-dimensional chiral structures the sense of perceived rotation remains unchanged for opposing directions of observation (think, for example, of a helix observed along its axis), planar chiral structures possess a sense of twist that is reversed when they are observed from opposite sides of the plane to which the structure belongs. Consequently, if planar chiral structures were to exhibit a polarization effect (due to this twist) for light incident normal to the plane, the sense of the effect would be reversed for light propagating in opposite directions. Such behavior has never been observed before, but if proven would be of profound benefit to the development of a new class of microwave and optical devices.In this paper we report such a polarization sensitive effect. It is a previously unknown fundamental phenomenon of electromagnetism that asymmetric materials can generate behaviors that in some ways resemble the famous non-reciprocity of the Faraday effect, which emerges when a wave propagates through a magnetized medium. However, the phenomenon reported here does not require the presence of a magnetic field and results from an electromagnetic wave's transmission through a chiral planar structure patterned on the sub-wavelength scale. Both in the Faraday effect and in that produced by planar chirality, the transmission and retardation of a circularly polarized wave are different in opposite directions. In both cases the polarization eigenstates, i.e. polarization states conserved on propagation, are elliptical (circular).There are also essential differences between the two phenomena. The asymmetry of the Faraday effect with respect to propagation in opposite directions applies to the transmission and retardation of the incident circularly polarized wave itself. The planar chirality effect leads to the (partial) conversion of the incident wave into one of opposite handedness, and it is the efficiency of this conversion that is as...

We report on a continuous electromagnetic metal planar metamaterial, which resembles a "fish scale" structure. Apart from the one isolated wavelength, it is highly transparent to electromagnetic radiation throughout a broad spectral range and becomes completely "invisible" at some frequency inflicting no transmission losses and phase delay. When the structure is superimposed on a metallic mirror it becomes a good broadband reflector everywhere apart from one wavelength where the reflectivity is small. At this wavelength the reflected wave shows no phase change with respect to the incident wave, thus resembling a reflection from a hypothetical zero refractive index material, or "magnetic wall." We also discovered that the structure acts as a local field concentrator and a resonant "amplifier" of losses in the underlying dielectric. DOI: 10.1103/PhysRevE.72.056613 PACS number͑s͒: 42.25.Bs, 78.66.Bz, 42.70.Ϫa, 78.67.Ϫn In optics, spectral selectivity in components such as filters, beam splitters, and mirrors has traditionally been realized by accurately engineering constructive and destructive multiple interference of light in a stack of dielectric layers with thicknesses comparable to the wavelength. Spectral selectivity of light transmission and reflection may also be found in regular three-dimensional structures commonly know as photonic band-gap crystals. However, another opportunity exists to achieve spectral selectivity of transmission and reflection in a thin, essentially subwavelength layer of material without engaging multiple beam diffraction and interference. Wavelength sensitive transmission and reflection of a thin layer may result from patterning the interface on a subwavelength scale in a way that makes electromagnetic excitation couple to the structure in a resonant fashion. The idea of frequency selective planar structures has been investigated in the microwave part of the spectrum for some time using arrays of separated holes in a metal screen or particles such as crosses, snowflakes, tapers, and split-ring resonators ͓1͔. Similar research on the extraordinary transmission of isotropic ͓2͔ and anisotropic ͓3͔ arrays of holes in the optical part of the spectrum has recently attracted a lot of attention. In this paper we point out, however, that to achieve narrow spectral resonances continuous periodic structures may be used.Here we report, to the best of our knowledge, the first experiential results on a new type of continuous planar metamaterial structure-an equidistant array of meandering metallic strips on a thin dielectric substrate producing a pattern that resembles fish scales. In the past similar structures have only been investigated theoretically ͓4,5͔. We show experimentally that the fish scale structure exhibits several interesting properties when interacting with electromagnetic radiation. First, it is highly transparent to electromagnetic radiation across a wide spectral range apart from one isolated wavelength. Second, when such a structure is combined with ͑superimposed on͒ a hom...

We report that electromagnetic wave reflected from a flat metallic mirror superimposed with a planar wavy metallic structure with subwavelength features that resemble “fish scales” reflects like a conventional mirror without diffraction, but shows no phase change with respect to the incident wave. Such unusual behavior resembles a reflection from a hypothetical zero refractive index material, or “magnetic wall”. We also discovered that the structure acts as a local field concentrator and a resonant “amplifier” of losses in the underlying dielectric.