Topic
Transformation optics
About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.
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TL;DR: In this paper, a chiral metamaterial with a broken four-fold symmetry of chiral structure was proposed to make the polarization plane of a linearly polarized electromagnetic wave reflected from its surface almost perpendicular to the polarization planes of the incident wave.
Abstract: Despite chiral metamaterials being widely appreciated for their giant optical activity and negative refractive index with respect to the transmitted electromagnetic waves, little research efforts are devoted to effects occurring upon optical reflection from such metamaterials. Here, we theoretically demonstrate highly energy-efficient cross-polarization conversion for a normally incident wave reflecting from metamaterial with a broken four-fold symmetry of chiral structure. We do this by designing metamaterial that makes the polarization plane of a linearly polarized electromagnetic wave reflected from its surface almost perpendicular to the polarization plane of the incident wave. Using reflection from this metamaterial, one can also freely convert between left-handed and right-handed circular polarizations without significant energy loss. The proposed chiral metamaterial may prove useful in electromagnetic communication systems, polarization controllable antennas, and on-chip biomedical sensors.
33 citations
TL;DR: In this paper, the scattering at a single interface between a uniform half-space and a bulk metamaterial has been studied and the scattering coefficients between plane waves and Bloch modes have been accurately computed.
Abstract: In order to better understand when man-made structures may be considered as metamaterials with effective properties at optical frequencies, we study the scattering (reflection, transmission) of light at a single interface between a uniform half-space and a bulk metamaterial, ie, a semi-infinite three-dimensional periodic structure We accurately compute the scattering coefficients between plane waves and Bloch modes and test the validity of the single-Bloch-mode approximation within the metamaterial The knowledge of the single-interface scattering coefficients allows us to propose an innovative method for deriving effective optical parameters
33 citations
TL;DR: This work demonstrates a low-loss metamaterial by exploiting dark bound states in dielectric inclusions coupled to the external waves by small nonresonant metallic antennas and shows that its resonance has a much larger quality factor than metal-based meta-atoms.
Abstract: Metamaterials--or artificial electromagnetic materials--can create media with properties unattainable in nature, but mitigating dissipation is a key challenge for their further development. Here, we demonstrate a low-loss metamaterial by exploiting dark bound states in dielectric inclusions coupled to the external waves by small nonresonant metallic antennas. We experimentally demonstrate a dispersion-engineered metamaterial based on a meta-atom made from alumina, and we show that its resonance has a much larger quality factor than metal-based meta-atoms. Finally, we show that our dielectric meta-atom can be used to create sheet metamaterials with negative permittivity or permeability.
33 citations
TL;DR: In this paper, a comprehensive derivation for the equation of geodesics in curved optical spaces is provided, and the resolution of the image of a line source radiating in the Maxwell fisheye and the Veselago-Pendry slab lens is analyzed.
Abstract: This paper reviews some properties of lenses in curved and folded optical spaces. The point of the paper is to show some limitations of geometrical optics in the analysis of subwavelength focusing. We first provide a comprehensive derivation for the equation of geodesics in curved optical spaces, which is a tool of choice to design metamaterials in transformation optics. We then analyse the resolution of the image of a line source radiating in the Maxwell fisheye and the Veselago–Pendry slab lens. The former optical medium is deduced from the stereographic projection of a virtual sphere and displays a heterogeneous refractive index n(r) which is proportional to the inverse of 1 + r 2. The latter is described by a homogeneous, but negative, refractive index. It has been suggested that the fisheye makes a perfect lens without negative refraction [Leonhardt, Philbin arxiv:0805.4778v2]. However, we point out that the definition of super-resolution in such a heterogeneous medium should be computed with respect...
32 citations
TL;DR: In this article, the authors showed that extreme-skin-depth (e-skid) waveguides can counterintuitively confine light better than the best-case all-dielectric design of high-index silicon waveguide surrounded by vacuum.
Abstract: Recently, we proposed a paradigm shift in light confinement strategy showing how relaxed total internal reflection and photonic skin-depth engineering can lead to sub-diffraction waveguides without metal [Optica1, 96 (2014)10.1364/OPTICA.1.000096OPTIC82334-2536]. Here, we show that such extreme-skin-depth (e-skid) waveguides can counterintuitively confine light better than the best-case all-dielectric design of high index silicon waveguides surrounded by vacuum. We also establish analytically that figures of merit related to light confinement in dielectric waveguides are fundamentally tied to the skin depth of waves in the cladding, a quantity surprisingly overlooked in dielectric photonics. We contrast the propagation characteristics of the fundamental mode of e-skid waveguides and conventional waveguides to show that the decay constant in the cladding is dramatically larger in e-skid waveguides, which is the origin of sub-diffraction confinement. We also propose an approach to verify the reduced photonic skin depth in experiment using the decrease in the Goos–Hanschen phase shift. Finally, we provide a generalization of our work using concepts of transformation optics where the photonic skin-depth engineering can be interpreted as a transformation on the momentum of evanescent waves.
32 citations