scispace - formally typeset
Search or ask a question

Showing papers on "Metamaterial absorber published in 2009"


Journal ArticleDOI
TL;DR: In this article, a polarization-insensitive metamaterial absorber for terahertz frequencies is presented, which achieves an absorptivity of 77% at 1.145 THz.
Abstract: We present the theory, design, and realization of a polarization-insensitive metamaterial absorber for terahertz frequencies. Effective-medium theory is used to describe the absorptive properties of the metamaterial in terms of optical constants---a description that has been thus far lacking. From our theoretical approach, we construct a device that yields over 95% absorption in simulation. Our fabricated design consists of a planar single unit-cell layer of metamaterial and reaches an absorptivity of 77% at 1.145 THz.

690 citations


Journal ArticleDOI
TL;DR: It is demonstrated theoretically that electromagnetically induced transparency can be achieved in metamaterials, in which electromagnetic radiation is interacting resonantly with mesoscopic oscillators rather than with atoms, and these results are confirmed by accurate simulations of the electromagnetic field propagation in the meetamaterial.
Abstract: We demonstrate theoretically that electromagnetically induced transparency can be achieved in metamaterials, in which electromagnetic radiation is interacting resonantly with mesoscopic oscillators rather than with atoms. We describe novel metamaterial designs that can support a full dark resonant state upon interaction with an electromagnetic beam and we present results of its frequency-dependent effective permeability and permittivity. These results, showing a transparency window with extremely low absorption and strong dispersion, are confirmed by accurate simulations of the electromagnetic field propagation in the metamaterial.

620 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed an approach to broad-band omnidirectional light absorption, based on light propagation in a metamaterial structure forming an effective "black hole".
Abstract: We develop an approach to broad-band omnidirectional light absorption, based on light propagation in a metamaterial structure forming an effective “black hole.” The proposed system does not rely on magnetic response, is nonresonant, and can be fabricated from existing materials.

495 citations


Journal ArticleDOI
TL;DR: In this paper, a dual-band metamaterial absorber with two distinct and strong absorption points near 0.45 and 0.92 THz has been designed and analyzed.
Abstract: We report the design, simulation, and measurement of a dual-band metamaterial absorber in the terahertz region. Theoretical and experimental results show that the absorber has two distinct and strong absorption points near 0.45 and 0.92 THz, both which are related to the LC resonance of the metamaterial. The distributions of the power flow and the power loss indicate that the absorber is an excellent electromagnetic wave collector: the wave is first trapped and reinforced in certain specific locations and then completely consumed. This dual-band absorber has applications in many scientific and technological areas.

478 citations


Journal ArticleDOI
TL;DR: In this paper, a PIMNIM that is subwavelength in all three dimensions enables absorption close to 100% for incidence angles up to 45° to the normal, and a specific implementation of such frequency-tunable PIMM based on plasmonic metamaterials is presented.
Abstract: A metamaterial-based approach in making a wide-angle absorber of infrared radiation is described. The technique is based on an anisotropic perfectly impedance-matched negative-index material PIMNIM .I t is shown analytically that a PIMNIM that is subwavelength in all three dimensions enables absorption close to 100% for incidence angles up to 45° to the normal. A specific implementation of such frequency-tunable PIMNIM based on plasmonic metamaterials is presented. Applications to infrared imaging and coherent thermal sources are described.

416 citations


Book
16 Nov 2009
TL;DR: Theory, design, and applications of metamaterials go beyond left-handed materials (LHM) or negative index materials (NIM) and focus on recent research activity as mentioned in this paper.
Abstract: Metamaterials:Theory, Design, and Applications goes beyond left-handed materials (LHM) or negative index materials (NIM) and focuses on recent research activity. Included here is an introduction to optical transformation theory, revealing invisible cloaks, EM concentrators, beam splitters, and new-type antennas, a presentation of general theory on artificial metamaterials composed of periodic structures, coverage of a new rapid design method for inhomogeneous metamaterials, which makes it easier to design a cloak, and new developments including but not limited to experimental verification of invisible cloaks, FDTD simulations of invisible cloaks, the microwave and RF applications of metamaterials, sub-wavelength imaging using anisotropic metamaterials, dynamical metamaterial systems, photonic metamaterials, and magnetic plasmon effects of metamaterials.

342 citations


Journal ArticleDOI
TL;DR: The terahertz metamaterials are artificial composites that acquire their electromagnetic properties from embedded subwavelength metallic structures and can be engineered to take on arbitrary values, including those not appearing in nature.
Abstract: Metamaterials are artificial composites that acquire their electromagnetic properties from embedded subwavelength metallic structures. In theory, the effective electromagnetic properties of metamaterials at any frequency can be engineered to take on arbitrary values, including those not appearing in nature. As a result, this new class of materials can dramatically add a degree of freedom to the control of electromagnetic waves. The emergence of metamaterials fortunately coincides with the intense emerging interest in terahertz radiation (T-rays), for which efficient forms of electromagnetic manipulation are sought. Considering the scarcity of naturally existing materials that can control terahertz, metamaterials become ideal substitutes that promise advances in terahertz research. Ultimately, terahertz metamaterials will lead to scientific and technological advantages in a number of areas. This article covers the principles of metamaterials and reviews the latest trends in terahertz metamaterial research from the fabrication and characterization to the implementation.

308 citations


Journal ArticleDOI
TL;DR: In this paper, a resonant microwave absorber based on a chiral metamaterial was proposed, which works well for a very wide range of incident angles for different polarizations.
Abstract: We propose a resonant microwave absorber based on a chiral metamaterial. We show, with both numerical simulations and experimental measurements, that the absorber works well for a very wide range of incident angles for different polarizations. The proposed absorber has a compact size and the absorption is close to one for a wide range of incident angles and it is a good candidate for potential applications.

256 citations


Journal ArticleDOI
TL;DR: The metamaterial modified bolometers modified by metallic resonant absorber elements are suitable for multispectral thermal imaging systems in the mid-IR and terahertz regime.
Abstract: Microbolometers are modified by metallic resonant absorber elements, leading to an enhanced responsivity at selectable wavelengths. The dissipative energy absorption of tailored metamaterials allows for engineering the response of conventional bolometer microbridges. The absorption peak position and height are determined by the geometry of the metamaterial. Square-shaped metal/dielectric/metal stacks as absorber elements show spectral resonances at wavelengths between 4.8 and 7.0 microm in accordance with numerical simulations. Total peak absorptions of 0.8 are obtained. The metamaterial modified bolometers are suitable for multispectral thermal imaging systems in the mid-IR and terahertz regime.

203 citations


Patent
David R. Smith1, Ruopeng Liu1, Tie Jun Cui1, Qiang Cheng1, Jonah N. Gollub1 
21 Aug 2009
TL;DR: In this paper, Babinet complements of split ring resonator (SRR) and electric LC (ELC) metamaterial elements are embedded in the bounding surfaces of planar waveguides, e.g. for beam steering/focusing devices, antenna array feed structures, etc.
Abstract: Complementary metamaterial elements provide an effective permittivity and/or permeability for surface structures and/or waveguide structures. The complementary metamaterial resonant elements may include Babinet complements of "split ring resonator" (SRR) and "electric LC" (ELC) metamaterial elements. In some approaches, the complementary metamaterial elements are embedded in the bounding surfaces of planar waveguides, e.g. to implement waveguide based gradient index lenses for beam steering/focusing devices, antenna array feed structures, etc..

122 citations


Journal ArticleDOI
TL;DR: By this TL model, the asymmetric phenomenon of THz absorption in MM absorber is unambiguously demonstrated, and it clarifies that strong absorption of this absorber under studied is mainly related to the LC resonance of the split-ring-resonator structure.
Abstract: Metamaterial (MM) absorber is a novel device to provide near-unity absorption to electromagnetic wave, which is especially important in the terahertz (THz) band. However, the principal physics of MM absorber is still far from being understood. In this work, a transmission line (TL) model for MM absorber was proposed, and with this model the S-parameters, energy consumption, and the power loss density of the absorber were calculated. By this TL model, the asymmetric phenomenon of THz absorption in MM absorber is unambiguously demonstrated, and it clarifies that strong absorption of this absorber under studied is mainly related to the LC resonance of the split-ring-resonator structure. The distribution of power loss density in the absorber indicates that the electromagnetic wave is firstly concentrated into some specific locations of the absorber and then be strongly consumed. This feature as electromagnetic wave trapper renders MM absorber a potential energy converter. Based on TL model, some design strategies to widen the absorption band were also proposed for the purposes to extend its application areas.

Journal ArticleDOI
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.

Book
05 Oct 2009
TL;DR: In this paper, the authors discuss the use of super-resolution and near-field enhancement with Layers of Resonant Arrays of Nanoparticles in the context of radio frequency communication.
Abstract: Part I: Super-resolution Negative-Refractive-Index Transmission-Line (NRI-TL) Metamaterial Lenses and Superlenses, A. K. Iyer and G. V. Eleftheriades Flat Lenses Formed by Photonic and Electromagnetic Crystals, P. A. Belov, C. R. Simovski, and P. Ikonen Subwavelength Imaging by Arrays of Metallic Rods, P. A. Belov, M. G. Silveirinha, C. R. Simovski, and Y. Hao Super Resolution and Near-Field Enhancement with Layers of Resonant Arrays of Nanoparticles, S. Steshenko, F. Capolino, S. Tretyakov, and C. R. Simovski Super-Resolution Imaging with Hyperlens, H. Lee, Yi Xiong, Zhaowei Liu, Cheng Sun, and Xiang Zhang Part II: Cloaking Cloaking and Transformation Media, U. Leonhardt and T. G. Philbin Scattering Cancellation and Plasmonic Cloaking, A. Alu and N. Engheta Electromagnetic Cloaks and Concentrators, A. D. Yaghjian, S. Maci, and E. Martini Part III: Circuit Applications in the Microwave, Millimeter Wave, and THz Frequency Ranges Application of Split Ring Resonators to Microwave Circuit Design, F. Martin and R. Marques Application of Electromagnetic Band Gaps to Microwave Circuit Design, J. Bonache, F. Falcone, I. Gil, J. Garcia-Garcia, and F. Martin Small andMultiband MNG Resonators: Spiral, Prefractal, and Other Geometries, P. J. Ferrer, J. M. Gonzalez-Arbesu, J. Romeu, J. Parron, G. Junkin, and R. Villarino Artificial Ferromagnetic Nanostructured Substrate for Planar Tunable Circuits, J. Spiegel, I. Huynen, L. Piraux, and A. Saib Microwave Phase Shifters and Filters Based on a Combination of Left-Handed and Right-Handed Transmission Lines, I. B. Vendik, D. V. Kholodnyak, and P. V. Kapitanova Magnetoinductive Waves II: Applications, O. Sydoruk, A. Radkovskaya, O. Zhuromskyy, E. Shamonina, and L. Solymar Part IV: Radiation Applications in the Microwave, Millimeter Wave, and THz Frequency Ranges CRLH Metamaterial Antennas, Part I: Theory and Antenna-Related Concepts, C. Caloz and T. Itoh CRLH Metamaterial Antennas, Part II: Leaky-Wave and Resonant Antennas, C. Caloz and T. Itoh Recent Developments of Metamaterial-Based and Metamaterial-Inspired Efficient Electrically Small Antennas, R. W. Ziolkowski and A. Erentok Application of Metamaterials to Microwave Patch and Leaky-Wave Antennas, L. Vegni, F. Bilotti, A. Alu, and N. Engheta Enhancement of Directivity by Using Metamaterial Substrates, P. Burghignoli, G. Lovat, F. Capolino, D. R. Jackson, and D. R.Wilton Metamaterial Antenna Applications, J (Yiannis) C. Vardaxoglou, R. D. Seager, J. A. Flint, and A. Chauraya High-Impedance Surfaces: Applications, A.P. Feresidis, G. Goussetis, A.B. Yakovlev, and C. R. Simovski Controllable Metamaterials for Telecoms: Principle, Design, and Applications. Applications in the GSM, GPRS, and UMTS Bands, F. Gadot and A. de Lustrac Optoelectronic Control of Metamaterials W. J. Padilla and R. D. Averitt Extraordinary Transmission as an Impedance-Matching Problem, F. Medina, F. Mesa, R. Marques, and D. C. Skigin Part V: Applications in the Optical Frequency Range Plasmonic Materials for Near-Field Optical Nanolithography, R. J. Blaikie Enhanced Transmission at Optical Frequencies, L. Martin-Moreno and F. J. Garcia-Vidal Photonic Crystals for Integrated Communication Systems, H. Benisty and J.-M. Lourtioz Photonic Applications of Two-Dimensional Quasicrystals, D. N. Chigrin and A. V. Lavrinenko Part VI: Fabrication Techniques for THz and Optical Metamaterials Fabrication and Optical Characterization of Photonic Metamaterials, S. Linden and M. Wegener Metamaterials at Optical Frequencies: Fabrication and Measurements, Nigel P. Johnson, R. M. De La Rue, and S. A. De La Rue Self-Organized Structures for Metamaterials, D. A. Pawlak Self-Assembly and Nanochemistry Techniques for the Fabrication of Metamaterials, V. Ponsinet, A. Aradian, P. Barois, and S. Ravaine

Proceedings ArticleDOI
31 May 2009
TL;DR: In this paper, a planar magnetic metamaterial fabricated using 3D direct laser writing and silver chemical vapor deposition as well as a negative-index bi-anisotropic metammaterial metallized via silver shadow evaporation was presented.
Abstract: We present a planar magnetic metamaterial fabricated using 3D direct laser writing and silver chemical vapor deposition as well as a negative-index bi-anisotropic metamaterial metallized via silver shadow evaporation. Calculations and experiments show good agreement.

Journal ArticleDOI
TL;DR: The design and experimental measurement of a powered active magnetic metamaterial with tunable permeability based on the combination of an embedded radiofrequency amplifier and a tunable phase shifter show that a negative permeability metamMaterial with zero loss or even gain can be achieved through an array of such meetamaterial cells.
Abstract: We report the design and experimental measurement of a powered active magnetic metamaterial with tunable permeability. The unit cell is based on the combination of an embedded radiofrequency amplifier and a tunable phase shifter, which together control the response of the medium. The measurements show that a negative permeability metamaterial with zero loss or even gain can be achieved through an array of such metamaterial cells. This kind of active metamaterial can find use in applications that are performance limited due to material losses.

Journal ArticleDOI
TL;DR: A structured metamaterial half-wave retarder that converts one linear polarization to its cross polarization is designed and its performance is characterized experimentally.
Abstract: Metamaterials with anisotropic electromagnetic properties have the capability to manipulate the polarization states of electromagnetic waves. We describe a method to design a broadband, low-loss wave retarder with graded constitutive parameter distributions based on non-resonant metamaterial elements. A structured metamaterial half-wave retarder that converts one linear polarization to its cross polarization is designed and its performance is characterized experimentally.

Journal ArticleDOI
TL;DR: A systematic study of a close-ring pair based freestanding metamaterial fabricated by double-layer, self-aligned photolithography, which reveals negative index of refraction in the frequency range of 0.66-0.90 THz under normal wave incidence.
Abstract: We present a systematic study of a close-ring pair based freestanding metamaterial fabricated by double-layer, self-aligned photolithography. Terahertz time-domain spectroscopy transmission measurements and numerical simulations have revealed negative index of refraction in the frequency range of 0.66-0.90 THz under normal wave incidence. The observed resonance behaviors can be well explained by a theoretical circuit model. The electromagnetic properties and the figure of merit of such close-ring metamaterials are also explored in terms of geometrical parameters of the unit cell with a goal of providing optimized design for three-dimensional metamaterials and potential device applications.

Journal ArticleDOI
TL;DR: In this paper, a review of the fundamentals of metamaterials with emphasis on negative-refractive-index ones, which are synthesized using loaded transmission lines, is presented.

Journal ArticleDOI
TL;DR: In this article, the authors presented a class of ultra-thin metamaterial absorbers, which consists of periodic microstrip lines on top of a planar lossy substrate backed by a conducting metallic plate.
Abstract: This paper presents a class of ultra-thin metamaterial absorbers, which consists of periodic microstrip lines on top of a planar lossy substrate backed by a conducting metallic plate. A highly efficient full-wave analysis method was developed to solve the electromagnetic response of the absorbers. The influence of electromagnetic properties of the substrate and physical dimensions of the microstrip lines were analyzed. Genetic algorithm was used to optimize the absorption bandwidth of the absorbers. Effective permeability and permittivity of the absorbers were retrieved to shed a new light on the absorption mechanism of the absorbers and to explain their ultimate bandwidth limit. It was found that the ultimate bandwidth limit of the metamaterial absorbers is the same as that of normal absorbers.

Journal ArticleDOI
TL;DR: In this article, a split-ring resonator (SRR) fabricated on flexible thin plastic films is investigated for the purpose of developing three-dimensional (3D) metamaterials in the terahertz region.
Abstract: Electromagnetic characteristics of a split-ring resonator (SRR) fabricated on flexible thin plastic films are investigated for the purpose of developing three-dimensional (3D) metamaterials in the terahertz region. Both electric and magnetic resonances are observed at frequencies determined by the structural parameters of the SRR. Since the optical path length of the plastic film is smaller than the wavelength of the resonant frequency of metamaterials, the diffraction effect is avoided in a 3D metamaterial. We also observe that each layer functions independently without interlayer interaction, indicating that the properties of the metamaterial are determined only by the unit cell design.

Journal ArticleDOI
TL;DR: In this article, a design for a polarization insensitive metamaterial absorber at 9.5 GHz by utilizing properly arranged resonant unit cells with orthogonal polarization sensitivity was presented.
Abstract: We present a design for a polarization insensitive metamaterial absorber at 9.5 GHz by utilizing properly arranged resonant unit cells with orthogonal polarization sensitivity. Full-wave electromagnetic simulation demonstrates nearly perfect microwave absorption, which has been verified by experimental measurement with a maximum absorption of about 92% for incident wave with different polarizations. Furthermore, we find such a metamaterial thin absorber could work for a wide incident angle ranging from 0° to 50° with absorption no less than 80% for both the transverse electric mode and transverse magnetic mode.

Journal ArticleDOI
TL;DR: In this article, a 3D metamaterial absorber operating at 11.8GHz was presented, which is composed of coplanar magnetic and electric resonators, with the latter in the center part of the former.
Abstract: In this paper, a 3-dimensional metamaterial absorber operating at 11.8GHz was presented. The metamaterial absorber is composed of coplanar magnetic and electric resonators, with the latter in the center part of the former. By carefully adjusting structural dimensions of magnetic and electric resonators, absorbance per unit cell can reach up to 96% at 11.8GHz with a 6% FWHM (Full Width at Half Maximum). The full-wave simulations conflrmed nearly equal permeability and permittivity and large imaginary part of the refractive index at 11.8GHz and thus proved the efiectiveness of the proposed 3-dimensional metamaterial absorber for microwave applications.

Journal ArticleDOI
Jiafu Wang, Shaobo Qu1, Zhuo Xu1, Hua Ma, Yiming Yang, Chao Gu, Xiang Wu 
TL;DR: In this article, a polarization-dependent wide-angle three-dimensional metamaterial absorber with a near-unity absorbance was presented, which is composed of coplanar electric and magnetic resonators.

Patent
28 Sep 2009
TL;DR: In this paper, a low-index metamaterial (LIM) is defined as a medium having a dielectric constant less than one with respect to electromagnetic waves at predetermined frequencies and propagating at grazing angles with respectto a surface of the low index meta-material.
Abstract: Various aspects of the disclosure provide low index metamaterials. The low index metamaterials may be used to form soft and/or hard electromagnetic (EM) boundaries to facilitate desired EM performance or propagation in applications including feed horns, spatial feed/combiners, isolation barriers between antennas or RF modules, and reduced radar cross- section applications. In one aspect, a low index metamaterial comprises a dielectric layer and a plurality of conductors on a surface of the dielectric layer, embedded in the dielectric layer or both, wherein the low index metamaterial appears as a medium having a dielectric constant less than one with respect to electromagnetic waves at predetermined frequencies and propagating at grazing angles with respect to a surface of the low index metamaterial.

Journal ArticleDOI
TL;DR: In this article, a modified effective medium theory was proposed to describe the metamaterial absorbers and the relationship of S-parameters and absorptance among them. And the power absorption distributions in these three structures were discussed in detail.
Abstract: We simulated the metamaterial absorbers in two propagation conditions and observed the universal phenomenon of strong non-reciprocity. It is found that this non-reciprocity cannot be well interpreted using the effective medium theory, which indicates that the designing and understanding for the metamaterial absorber based on the proposed effective medium theory could not be applicable. The reason is pointed out that the metamaterial absorber does not satisfy the homogeneous-effective limit. So we put forward a three-parameter modified effective medium theory to fully describe the metamaterial absorbers. We have also investigated the relationships of S-parameters and absorptance among the metamaterial absorbers and the two components inside. Then the power absorption distributions in these three structures are discussed in detail. It can be concluded that the absorption is derived from the ERR structure and is enhanced largely by the coupling mechanism, and the strong non-reciprocity results from the different roles which wire structure plays in both propagation conditions.

Proceedings ArticleDOI
11 Jun 2009
TL;DR: In this article, a method to evaluate the shielding performance of a metamaterial slab consisting of arbitrary-shaped metallic inclusions in a dielectric host is proposed, which is considered for both resonant and non-resonant inclusions.
Abstract: Metamaterials can prove to be good candidates for shields in EMC applications where weight reduction is a challenge. Indeed metamaterial slabs can provide the same reflective properties as conventional metallic screens but with a lower density and reduced weight. Another advantage is that they can be tailored to exhibit required frequency-selective properties. However, their performance in terms of shielding performance has yet to be evaluated. In this paper, a method to evaluate the shielding performance of a metamaterial slab consisting of arbitrary-shaped metallic inclusions in a dielectric host is proposed. The specific case of periodic metamaterials will be considered for both resonant and non-resonant inclusions in the effective-homogeneity limit.

01 Jan 2009
TL;DR: In this article, a novel absorbing structure in microwave range with metamaterial frequency selective surface (FSS) is presented, which demonstrates a peak absorbance greater than 87% at 12.8GHz.
Abstract: Artiflcially constructed electromagnetic metamaterials have attracted much in- terest recently. A novel absorbing structure in microwave range with metamaterial frequency selective surface (FSS) is presented in this paper. The absorber is a simple unit cell layer planar structure based upon two metamaterial resonators that couple separately electric and magnetic flelds so as to absorb almost all incident flelds. The resulting structure which consists of metallic elements has superior absorbance characteristics compared to conventional passive absorbers of corresponding thickness. Experimental results are presented and compared to obtained from a flnite difierence time domain (FDTD) approach, demonstrates a peak absorbance greater than 87% at 12.8GHz. 1. INTRODUCTION Artiflcially constructed electromagnetic metamaterials have attracted much interest recently due to the potential to produce exotic electromagnetic phenomena such as negative index of refraction (1,2) or the possibility to fabricate an invisible device such as an electromagnetic cloak (3). The realiza- tion of such properties lies in these materials which response to incident radiation have the opposite direction between the group velocity, which characterizes the ∞ow of energy, and the phase velocity, which characterizes the movement of the wave fronts. The electromagnetic metamaterial structures which are very freedom in geometrically have been widely used in every technologically relevant frequency distribution range from radio to optical (4{8), due to their low loss, low cost and ∞exi- bility in adjusting the frequency. Recently these exotic characteristics which the electromagnetic metamaterial constructions have behaved demonstrate great presage for future application. After the early work of Veselago (9), research enthusiasm about negative index materials has been in a recession, because no naturally occurring material meet simultaneously with " < 0 and " < 0 in a frequency band (10). The situation changed in 2000, however, when a composite structure based on split ring resonators (SSRs) was presented and demonstrated existing a frequency band over which " and " were both negative. As such, the primary focus has been on the characteristic impedance of the media for propagating electromagnetic wave deflned as, where a metamaterial can be impedance-matched to free space by matching " and ", minimizing re∞ectivity. As we know, metamaterials can be regarded as efiective media and characterized by a complex electric permit- tivity and complex magnetic permeability. The electric loss and magnetic loss of metamaterial can be respectively characterized by the ratio of the imaginary and real part of electric permittivity tg-" = "2="1, and the ratio of the imaginary and real part of magnetic permeability tg-" = "2="1, the more its value, the higher the rate of absorption of the metamaterial. The loss componements of the media constant ("2 and "2) have much potential for the creation of exotic and useful materials as well. In this paper, a novel absorbing structure which shows a high absorbance and can be used in some devices such as bolometric wave detector. 2. DESIGN

Journal ArticleDOI
TL;DR: In this article, the authors theoretically demonstrate control of the plasma-like effective response of a metamaterial composed of aligned metallic nanorods when the electric field of the incident radiation is parallel to the nanorod arrays.
Abstract: We theoretically demonstrate control of the plasma-like effective response of a metamaterial composed of aligned metallic nanorods when the electric field of the incident radiation is parallel to the nanorods. By embedding this metamaterial in a coherent atomic/molecular medium, for example silver nanorod arrays submerged in sodium vapor, we can make the metamaterial transmittive in the forbidden frequency region below its plasma frequency. This phenomenon is enabled by having Lorentz absorbers or other coherent processes like stimulated Raman absorption in the background medium which provide a large positive dielectric permittivity in the vicinity of the resonance, thereby rendering the effective permittivity positive. In particular, processes such as electromagnetically induced transparency are shown to provide additional control to switch and tune the new transmission bands.

Dissertation
24 Sep 2009
TL;DR: Iyer et al. as mentioned in this paper presented the first experimental verification of free-space Veselago-Pendry superlensing using a new class of volumetric metamaterials based on 2D NRI-TL layers that, although polarization specific, may be easily constructed using available lithographic techniques to interact with free space sources.
Abstract: Free-Space Metamaterial Superlenses using Transmission-Line Techniques Ashwin K. Iyer Doctor of Philosophy Graduate Department of Electrical Engineering University of Toronto 2009 Free-space imaging with a resolution beyond that dictated by the classical diffraction limit may be achieved with a ‘Veselago-Pendry’ superlens made from a metamaterial possessing a number of specific properties, including a negative refractive index (NRI). Although a planar NRI transmission-line (NRI-TL) metamaterial based on the periodic lumped loading of a host TL network has successfully verified the phenomenon of superlensing in a 2D microstrip environment, a true Veselago-Pendry superlens capable of interacting with and manipulating fields in free space remained elusive, largely due to the difficulty of meeting its stringent design constraints and also to the problem of realizing a full 3D isotropic, polarization-independent structure. This work presents the first experimental verification of free-space Veselago-Pendry superlensing using a new class of volumetric metamaterials based on 2D NRI-TL layers that, although polarizationspecific, may be easily constructed using available lithographic techniques to interact with free-space sources. An equivalent-circuit model is developed to enable accurate design of the metamaterial’s dispersion and transmission characteristics, including those associated with Veselago-Pendry superlensing, and is validated using full-wave simulations. First, a volumetric NRI-TL metamaterial employing fully printed loading elements is fabricated to verify the salient properties of a free-space metamaterial-slab lens. This lens demonstrates diffraction-limited focusing at X-band and, thus, affirms theoretical results that suggest that electrically thick and lossy metamaterials are unable to perform

Journal ArticleDOI
TL;DR: In this article, the authors analyzed the electromagnetic response of nanostructured metamaterials to evanescent waves at optical frequency via the finite-difference time-domain simulatioins on parallel computer.
Abstract: Metamaterial with negative permittivity and permeability is studied by means of computer simulations. We analyze the electromagnetic response of nanostructured metamaterials to evanescent waves at optical frequency via the finite-difference time-domain simulatioins on parallel computer. Effects of the nanostructure on dielectric and magnetic properties are taken into account by introducing the Drude-Lorentz model in the materials dispersion. Size effect on the dispersion is examined by comparing the model with that of a noble metal particle. A re-focusing and an amplification of the evanescent waves propagating through a metamaterial, consisting of metal slabs/vacuum stacking, are demonstrated for the frequency range at 614–744 THz. By properly treating the materials dispersion, we show that the nanostructured metamaterial may behave as a left-handed material in the optical range. [doi:10.2320/matertrans.MC200822]