Composite Medium with Simultaneously Negative Permeability and Permittivity

Smith, David R.; Padilla, Willie J.; Vier, D. C.; Nemat‐Nasser, Sia; Schultz, S.

doi:10.1103/physrevlett.84.4184

Cited by 7,848 publications

(4,399 citation statements)

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“…Artificially engineered materials with specific EM properties, known as metamaterials [1,2], have been used to control the propagation of EM waves, and have recently 2 been applied to cloaking through transformation optics [3][4][5][6][7][8]. The invariance of Maxwell's equations under optical coordinate transformation allows the space around the object to be reshaped such that the light can propagate in the desired way.…”

Section: Introductionmentioning

confidence: 99%

A Carpet Cloak for Visible Light

et al. 2011

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ABSTRACT:We report an invisibility carpet cloak device, which is capable of making an object undetectable by visible light. The cloak is designed using quasi conformal mapping and is fabricated in a silicon nitride waveguide on a specially developed nano-porous silicon oxide substrate with a very low refractive index. The spatial index variation is realized by etching holes of various sizes in the nitride layer at deep subwavelength scale creating a local effective medium index. The fabricated device demonstrates wideband invisibility throughout the visible spectrum with low loss. This silicon nitride on low index substrate can also be a general scheme for implementation of transformation optical devices at visible frequency. KEYWORDS:Optical metamaterials, invisibility cloak, optical transformation Invisibility cloaks, a family of optical illusion devices that route electromagnetic (EM) waves around an object so that the existence of the object does not perturb light propagation, are still in their infancy. Artificially engineered materials with specific EM properties, known as metamaterials [1,2], have been used to control the propagation of EM waves, and have recently 2 been applied to cloaking through transformation optics [3][4][5][6][7][8]. The invariance of Maxwell's equations under optical coordinate transformation allows the space around the object to be reshaped such that the light can propagate in the desired way. Such transformations usually require EM properties with extreme values that are only achievable in metallic metamaterials, and have been experimentally demonstrated for cloaking in microwave frequencies [9,10]. Due to the significant metallic loss at optical frequencies, the implementation of such cloaks for visible light has been difficult. Recently another innovative strategy was developed based on exploiting uniaxial crystals [11,12]. These devices have demonstrated cloaking in visible frequencies for a certain polarization of light based on intrinsic anisotropy in the crystals. As an alternative, conformal mapping, where an inverse transformation of the electrical permittivity and magnetic permeability leads to a spatially variable refractive index profile [13], can be applied to isotropic dielectric metamaterials. While 3D conformal mapping leads to anisotropic index profiles [14], a 2D quasi conformal mapping (QCM) can be employed to minimize anisotropy. The 2D QCM is the basis for the carpet cloak [15], where the object is hidden under a reflective layer (the carpet). To achieve cloaking, the raised protrusion (the bump) created in the reflective layer is mapped to a flat plane and the resulting 2D index profile forms a carpet cloak device. In contrast to resonant optical structures [16,17], QCM carpet cloak provides a broadband loss-less design and may be invariably extended in the third direction with some limitations [18], experimentally demonstrated to operate for a range of viewing angles [19]. The relatively modest materials requirement from QCM enabled the implementation of the...

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Section: Introductionmentioning

confidence: 99%

A Carpet Cloak for Visible Light

et al. 2011

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“…D.R Smith proposed two different excitation schemes for this composite [3]. The first one corresponds to the H || excitation in which the external magnetic field is oriented parallel to the axis of the SRR( perpendicular to the SRR plane) and the E-field is oriented parallel to the splits.…”

Section: The H ┴ Excitation Of Srr and Wire Pairsmentioning

confidence: 99%

“…D. R Smith et.al. practically demonstrated the negative refractive index medium by combining the split ring resonator and continuous wire arrays [3]. The peculiar propagation characteristics of negative refractive index materials give rise to different electromagnetic applications like reverse Snell's law, subwavelength focusing etc.…”

Section: Introductionmentioning

confidence: 99%

A Metamaterial Backed Dipole Antenna for High Gain Directional Communications

Sarin¹,

Jayakrishnan²,

Aanandan³

et al. 2016

AEM

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The enhanced radiation performance of a dipole antenna backed by the split ring resonator-continuous wire pair array working in the H ┴ excitation scenario is presented in this paper. The H ┴ excitation scenario of the metamaterial is used to get zero reflection phase resulting in enhanced gain performance. The two layer meta-structure along with the dipole is fabricated on a low cost substrate of dielectric constant 4.4 and height 1mm. The reflection and transmission characteristics of the metamaterial structure and its effect on the radiation performance of the dipole antenna are presented in this paper.

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“…[1][2][3][4] A split ring resonator (SRR) is one of the typical metamaterials structures. In order to extend its resonance bandwidth, terahertz metamaterials with resonance tunability were developed recently.…”

Section: Doi: 101002/adma201104575mentioning

confidence: 99%