Metamaterial absorber with dendritic cells at infrared frequencies
01 Dec 2009-Journal of The Optical Society of America B-optical Physics (Optical Society of America)-Vol. 26, Iss: 12, pp 2382-2385
TL;DR: In this paper, a model of an infrared metamaterial absorber composed of metal dendritic resonators, dielectric substrate, and continuous metal film is presented, and numerical simulation confirms an absorptivity of 98.6% at the infrared wavelength of 2.79 μm.
Abstract: We present a model of an infrared metamaterial absorber composed of metal dendritic resonators, dielectric substrate, and continuous metal film. Numerical simulation confirms an absorptivity of 98.6% at the infrared wavelength of 2.79 μm. The proposed metamaterial absorber has an excellence of two-dimensional isotropy, and it could be fabricated with a chemical double-template technique. Our simulation shows it could be operated for a wide range of incident angles. The optical metamaterial absorber proposed in this paper has potential applications such as in infrared imaging devices, thermal bolometers, and wavelength-selective radiators.
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TL;DR: In this article, a series of plasmonic and metamaterial structures can work as efficient narrowband absorbers due to the excitation of plasmic or photonic resonances, providing a great potential for applications in designing selective thermal emitters, biosensing, etc.
Abstract: Electromagnetic absorbers have drawn increasing attention in many areas. A series of plasmonic and metamaterial structures can work as efficient narrowband absorbers due to the excitation of plasmonic or photonic resonances, providing a great potential for applications in designing selective thermal emitters, biosensing, etc. In other applications such as solar-energy harvesting and photonic detection, the bandwidth of light absorbers is required to be quite broad. Under such a background, a variety of mechanisms of broadband/multiband absorption have been proposed, such as mixing multiple resonances together, exciting phase resonances, slowing down light by anisotropic metamaterials, employing high loss materials and so on.
455 citations
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TL;DR: A series of plasmonic and metamaterial structures can work as efficient narrow band absorbers, providing a great potential for applications in designing selective thermal emitters, bio-sensing, etc as mentioned in this paper.
Abstract: Electromagnetic absorbers have drawn increasing attention in many areas. A series of plasmonic and metamaterial structures can work as efficient narrow band absorbers due to the excitation of plasmonic or photonic resonances, providing a great potential for applications in designing selective thermal emitters, bio-sensing, etc. In other applications such as solar energy harvesting and photonic detection, the bandwidth of light absorbers is required to be quite broad. Under such a background, a variety of mechanisms of broadband/multiband absorption have been proposed, such as mixing multiple resonances together, exciting phase resonances, slowing down light by anisotropic metamaterials, employing high loss materials and so on.
433 citations
TL;DR: In this paper, the progress in some materials and structures for electromagnetic applications, such as microwave absorption, electric shielding and antenna designs, which have been developed in recent years are summarized.
Abstract: This review aims to summarise the progress in some materials and structures for electromagnetic applications, such as microwave absorption, electric shielding and antenna designs, which have been developed in recent years. Composites with spherical powders for microwave absorption focus mainly on those based on ferrites (especially hexagonal), carbonyl iron and related alloys and various newly emerged nanosized materials. Composites with long conductive fibres as fillers will be summarised, with speical attentions to prediction, measurment and evaluation of their performances. Metamaterials include structures for microwave absorbing applications, tunable materials or structures with reflection or transmission coefficients that are tunable by external magnetic or electric fields, and specially designed structures for microwave absorbing applications, with thickness much smaller than that of conventional composite materials and performances that can be optimised by the physical properties of substra...
378 citations
TL;DR: This paper demonstrates a conformal metamaterial absorber with a narrow band, polarization-independent absorptivity of >90% over a wide ±50° angular range centered at mid-infrared wavelengths of 3.3 and 3.9 μm, making it attractive for advanced coatings that suppress the infrared reflection from the protected surface.
Abstract: Metamaterials offer a new approach to create surface coatings with highly customizable electromagnetic absorption from the microwave to the optical regimes. Thus far, efficient metamaterial absorbers have been demonstrated at microwave frequencies, with recent efforts aimed at much shorter terahertz and infrared wavelengths. The present infrared absorbers have been constructed from arrays of nanoscale metal resonators with simple circular or cross-shaped geometries, which provide a single band response. In this paper, we demonstrate a conformal metamaterial absorber with a narrow band, polarization-independent absorptivity of >90% over a wide ±50° angular range centered at mid-infrared wavelengths of 3.3 and 3.9 μm. The highly efficient dual-band metamaterial was realized by using a genetic algorithm to identify an array of H-shaped nanoresonators with an effective electric and magnetic response that maximizes absorption in each wavelength band when patterned on a flexible Kapton and Au thin film substrat...
310 citations
TL;DR: In this paper, a polarization-insensitive metamaterial (MM) absorber is presented, which is composed of the dielectric substrate sandwiched with split-ring-cross resonator (SRCR) and continuous metal film.
Abstract: In this paper, we present a polarization-insensitive metamaterial (MM) absorber which is composed of the dielectric substrate sandwiched with split-ring-cross resonator (SRCR) and continuous metal film. The MM absorber is not limited by the quarter-wavelength thickness and can achieve near-unity absorbance by properly assembling the sandwiched structure. Microwave experiments demonstrate the maximum absorptivity to be about 99% around 10.91 GHz for incident wave with different polarizations. The surface currents distributions of the resonance structure are discussed to look into the resonance mechanism. Importantly, our absorber is only 0.4 mm thick, and numerical simulations confirm that the MM absorber could achieve very high absorptivity at wide angles of incidence for both transverse electric (TE) wave and transverse magnetic (TM) wave. The sandwiched structure is also suitable for designing of a THz and even higher frequency MM absorber, and simulations demonstrate the absorption of 99% at 1.105 THz.
186 citations
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TL;DR: These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root ofɛ·μ for the frequencies where both the permittivity and the permeability are negative.
Abstract: We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of copper strips and split ring resonators on interlocking strips of standard circuit board material. By measuring the scattering angle of the transmitted beam through a prism fabricated from this material, we determine the effective n, appropriate to Snell's law. These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root of epsilon.mu for the frequencies where both the permittivity (epsilon) and the permeability (mu) are negative. Configurations of geometrical optical designs are now possible that could not be realized by positive index materials.
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TL;DR: In this paper, it was shown that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu/sub eff/, which can be tuned to values not accessible in naturally occurring materials.
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8,135 citations
TL;DR: This work describes here the first practical realization of a cloak of invisibility, constructed with the use of artificially structured metamaterials, designed for operation over a band of microwave frequencies.
Abstract: A recently published theory has suggested that a cloak of invisibility is in principle possible, at least over a narrow frequency band. We describe here the first practical realization of such a cloak; in our demonstration, a copper cylinder was "hidden" inside a cloak constructed according to the previous theoretical prescription. The cloak was constructed with the use of artificially structured metamaterials, designed for operation over a band of microwave frequencies. The cloak decreased scattering from the hidden object while at the same time reducing its shadow, so that the cloak and object combined began to resemble empty space.
6,830 citations
TL;DR: This work fabricate, characterize, and analyze a MM absorber with a slightly lower predicted A(omega) of 96%.
Abstract: We present the design for an absorbing metamaterial (MM) with near unity absorbance A(omega). Our structure consists of two MM resonators that couple separately to electric and magnetic fields so as to absorb all incident radiation within a single unit cell layer. We fabricate, characterize, and analyze a MM absorber with a slightly lower predicted A(omega) of 96%. Unlike conventional absorbers, our MM consists solely of metallic elements. The substrate can therefore be optimized for other parameters of interest. We experimentally demonstrate a peak A(omega) greater than 88% at 11.5 GHz.
5,550 citations