DOCSLIB.ORG

Advanced Metamaterials for High Resolution Focusing and Invisibility Cloaks

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Advanced Metamaterials for High Resolution Focusing and Invisibility Cloaks Doctoral thesis submitted for the degree of Doctor of Philosophy in Telecommunication Engineering Postgraduate programme: Communication Technology Advanced metamaterials for high resolution focusing and invisibility cloaks Presented by: Bakhtiyar Orazbayev Director: Dr. Miguel Beruete Díaz Pamplona, November 2016 Abstract Metamaterials, the descendants of the artificial dielectrics, have unusual electromagnetic parameters and provide more abilities than naturally available dielectrics for the control of light propagation. Being able to control both permittivity and permeability, metamaterials have opened a way to obtain a double negative medium. The first experimental realization of such medium gave an enormous impulse for research in the field of electromagnetism. As result, many fascinating electromagnetic devices have been developed since then, including metamaterial lenses, beam steerers and even invisibility cloaks. The possible applications of metamaterials are not limited to these devices and can be applied in many fields, such as telecommunications, security systems, biological and chemical sensing, spectroscopy, integrated nano-optics, nanotechnology, medical imaging systems, etc. The aim of this doctoral thesis, performed at the Public University of Navarre in collaboration with the University of Texas at Austin, the Valencia Nanophotonics Technology Center in the UPV and King’s College London, is to contribute to the development of metamaterial based devices, including their fabrication and, when possible, experimental verification. The thesis is not focused on a single application or device, but instead tries to provide an extensive exploration of the different metamaterial devices. These results include the following: Three different lens designs based on a fishnet metamaterial are presented: a broadband zoned fishnet metamaterial lens, a Soret fishnet metamaterial lens and a Wood zone plate fishnet metamaterial. All lenses have been experimentally realized, demonstrating a good agreement with numerical analysis. Moreover, a metasurface, a 2D case of metamaterial, built with closed ring resonators has been used to design an ultrathin carpet cloak. Numerical as well as experimental analysis is done, confirming the cloaking performance of the designed cloak in relatively wide frequency range and angle span. Also, a design of a transformation based cloak for diffusive light is presented. It is demonstrated, that by restricting the cloak to work in one direction it is possible to obtain an ideal cloaking performance under transient illumination, which is normally beyond reach in typical cloak designs. Finally, the theoretical demonstration of three different beam steering devices based on graphene metamaterial is presented. The used graphene metamaterial allows to dynamically control the output angle of the radiation with ultrahigh speed. i ii Resumen Los metamateriales, descendientes de los dieléctricos artificiales, tienen parámetros electromagnéticos inusuales y proporcionan más posibilidades que los dieléctricos naturales para el control de la propagación de la luz. Los metamateriales han posibilitado la obtención de medios doblemente negativos, gracias a la capacidad que ofrecen para controlar tanto la permitividad y la permeabilidad. La primera realización experimental de un medio de ese tipo dio un enorme impulso a la investigación en el campo del electromagnetismo. Como resultado, se han desarrollado desde entonces muchos dispositivos electromagnéticos fascinantes, incluyendo lentes de metamateriales, dispositivos de control de dirección de haz e incluso capas de invisibilidad. Las posibles aplicaciones de los metamateriales no se limitan a estos dispositivos y se pueden aplicar en muchas áreas como las telecomunicaciones, sistemas de seguridad, detección biológica y química, la espectroscopía, nanoóptica integrada, la nanotecnología, los sistemas de imágenes médicas, etc. El objetivo de esta tesis doctoral, realizada en la Universidad Pública de Navarra en colaboración con la Universidad de Texas en Austin, el Centro de Tecnología Nanofotónica de Valencia de la UPV y el King’s College London, es contribuir al desarrollo de dispositivos basados en metamateriales, incluyendo su fabricación y, cuando sea posible, la verificación experimental. La tesis no se centra en una sola aplicación o dispositivo, sino que trata de proporcionar una extensa exploración de diferentes dispositivos de metamateriales. Los resultados de la misma son los siguientes: Se presentan tres lentes de diferentes diseños basados en un metamaterial fishnet: una lente zonada de ancha banda, una lente Soret y una lente de Wood. Todas las lentes han sido experimentalmente realizadas, demostrando un buen acuerdo con el análisis numérico. Por otra parte, se ha demostrado una capa de invisibilidad ultrafina basada en una metasuperficie, un caso 2D de metamaterial, construida con resonadores de anillo. Se ha realizado un análisis numérico, y experimental confirmando el comportamiento de invisibilidad dentro de un rango de frecuencias y de ángulos relativamente amplios. Además, se presenta un diseño de una capa de invisibilidad basada en la óptica de transformación para la luz difusa. Se demuestra, que mediante la restricción de la capa para trabajar en una sola dirección es posible obtener un rendimiento de camuflaje ideal bajo las condiciones de iluminación transitoria, que normalmente está fuera de alcance en los diseños típicos de capas de invisibilidad. Por último, se presenta la demostración teórica de tres diferentes dispositivos de control del haz basados en metamateriales de grafeno. El metamaterial de grafeno utilizado permite controlar dinámicamente el ángulo de salida de la radiación con velocidad ultra alta. iii iv Acknowledgments I would like to take this chance to extend my gratitude to all people who helped me during my study. The thesis would not be accomplished without their help. However, it is not possible to include all of them in this short acknowledgement. Hope those people I missed out in the following can accept my sincere appreciation at this moment. At first, I would like to express my gratitude to my supervisor Dr. Miguel Beruete for his excellent guidance (not just scientific). His advices and encouragement have been of vital importance during my research work. I also would like to thank and Dr. Francisco Falcone for his constant support during my study. Thanks then goes to Dr. Miguel Navarro-Cía and Dr. Irina Khromova. The valuable discussions with them, their advices, and experienced instruction helped greatly with my research work. I want to give my special thanks to Prof. Mario Sorolla, who unfortunately passed away. Without him it would have been impossible to make this work. In the Department of Electronic and Electrical Engineering, there are still more people I want to thank. I would like to thank to Prof. Andrea Alù from University of Texas, Prof. Alejandro Martínez and Dr. Carlos García-Meca from Universitat Politècnica de València, Prof. Anatoly Zayats from King’s College London for giving me the opportunity of being part of their research groups and so improving my quality as a researcher. Thanks to all people that I met in Austin and Valencia, particularly to Jason, Eun, Romain, Alba, Luis and Álvaro, for making me feel like if I never would have left home. During my study in Spain, I am lucky to have the company of my friends and colleagues: Laura, Unai, Aitziber, Daniel, Víctor, Pablo, Alicia, Amagoia, Jose, Adur and Dr. Torres. Without them, my years in Pamplona would not have been as pleasant. I acknowledge Spanish Ministerio de Economía y Competitividad for the financial support (under grant FPI BES-2012-054909) of my study at UPNA. Last, but of course not least, I thank my parents for their love and support all the time. v vi Agradecimientos Me gustaría aprovechar esta oportunidad para expresar mis agradecimientos a todas las personas que me ayudaron durante mi estudio. La tesis no se llevaría a cabo sin su ayuda. Sin embargo, no es posible incluir todos ellos en estos breves agradecimientos. Espero que las personas que se me pasó mencionar aquí puedan aceptar mi agradecimiento sincero en este momento. En primer lugar, me gustaría expresar mi agradecimiento a mi supervisor el Dr. Miguel Beruete por su excelente orientación (no sólo científica). Sus consejos y ánimo han sido de vital importancia durante mi trabajo de investigación. También me gustaría dar las gracias y el Dr. Francisco Falcone por su constante apoyo durante mi estudio. Gracias a continuación al Dr. Miguel Navarro-Cía y el Dr. Irina Khromova. Las valiosas discusiones con ellos, sus consejos, y la instrucción con experiencia ayudaron mucho con mi trabajo de investigación. Quiero dar las gracias especialmente al Prof. Mario Sorolla, que lamentablemente falleció. Sin él habría sido imposible realizar este trabajo. En el Departamento de Ingeniería Eléctrica y Electrónica, todavía hay más gente que quiero agradecer. Me gustaría dar las gracias al Prof. Andrea Alù de la Universidad de Texas, el Prof. Alejandro Martínez y el Dr. Carlos García-Meca desde Universidad Politécnica de Valencia, el Prof. Anatoly Zayats del King College de Londres por darme la oportunidad de ser parte de sus grupos de investigación y así mejorar la calidad de mi como investigador. Gracias a todas las personas que conocí en Austin y Valencia, sobre todo a Jason, Eun, Romain, Alba, Luis y Álvaro, por hacerme sentir como si nunca hubiera salido de casa. Durante
Load more

Recommended publications
  • Far-Field Optical Imaging of Viruses Using Surface Plasmon Polariton
    Magnifying superlens in the visible frequency range. I.I. Smolyaninov, Y.J.Hung , and C.C. Davis Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA Optical microscopy is an invaluable tool for studies of materials and biological entities. With the current progress in nanotechnology and microbiology imaging tools with ever increasing spatial resolution are required. However, the spatial resolution of the conventional microscopy is limited by the diffraction of light waves to a value of the order of 200 nm. Thus, viruses, proteins, DNA molecules and many other samples are impossible to visualize using a regular microscope. The new ways to overcome this limitation may be based on the concept of superlens introduced by J. Pendry [1]. This concept relies on the use of materials which have negative refractive index in the visible frequency range. Even though superlens imaging has been demonstrated in recent experiments [2], this technique is still limited by the fact that magnification of the planar superlens is equal to 1. In this communication we introduce a new design of the magnifying superlens and demonstrate it in the experiment. Our design has some common features with the recently proposed “optical hyperlens” [3], “metamaterial crystal lens” [4], and the plasmon-assisted microscopy technique [5]. The internal structure of the magnifying superlens is shown in Fig.1(a). It consists of the concentric rings of polymethyl methacrylate (PMMA) deposited on the gold film surface. Due to periodicity of the structure in the radial direction surface plasmon polaritons (SPP) [5] are excited on the lens surface when the lens is illuminated from the bottom with an external laser.
    [Show full text]
  • Optical Negative-Index Metamaterials
    REVIEW ARTICLE Optical negative-index metamaterials Artifi cially engineered metamaterials are now demonstrating unprecedented electromagnetic properties that cannot be obtained with naturally occurring materials. In particular, they provide a route to creating materials that possess a negative refractive index and offer exciting new prospects for manipulating light. This review describes the recent progress made in creating nanostructured metamaterials with a negative index at optical wavelengths, and discusses some of the devices that could result from these new materials. VLADIMIR M. SHALAEV designed and placed at desired locations to achieve new functionality. One of the most exciting opportunities for metamaterials is the School of Electrical and Computer Engineering and Birck Nanotechnology development of negative-index materials (NIMs). Th ese NIMs bring Center, Purdue University, West Lafayette, Indiana 47907, USA. the concept of refractive index into a new domain of exploration and e-mail: [email protected] thus promise to create entirely new prospects for manipulating light, with revolutionary impacts on present-day optical technologies. Light is the ultimate means of sending information to and from Th e arrival of NIMs provides a rather unique opportunity for the interior structure of materials — it packages data in a signal researchers to reconsider and possibly even revise the interpretation of zero mass and unmatched speed. However, light is, in a sense, of very basic laws. Th e notion of a negative refractive index is one ‘one-handed’ when interacting with atoms of conventional such case. Th is is because the index of refraction enters into the basic materials. Th is is because from the two fi eld components of light formulae for optics.
    [Show full text]
  • Super-Resolution Imaging by Dielectric Superlenses: Tio2 Metamaterial Superlens Versus Batio3 Superlens
    hv photonics Article Super-Resolution Imaging by Dielectric Superlenses: TiO2 Metamaterial Superlens versus BaTiO3 Superlens Rakesh Dhama, Bing Yan, Cristiano Palego and Zengbo Wang * School of Computer Science and Electronic Engineering, Bangor University, Bangor LL57 1UT, UK; [email protected] (R.D.); [email protected] (B.Y.); [email protected] (C.P.) * Correspondence: [email protected] Abstract: All-dielectric superlens made from micro and nano particles has emerged as a simple yet effective solution to label-free, super-resolution imaging. High-index BaTiO3 Glass (BTG) mi- crospheres are among the most widely used dielectric superlenses today but could potentially be replaced by a new class of TiO2 metamaterial (meta-TiO2) superlens made of TiO2 nanoparticles. In this work, we designed and fabricated TiO2 metamaterial superlens in full-sphere shape for the first time, which resembles BTG microsphere in terms of the physical shape, size, and effective refractive index. Super-resolution imaging performances were compared using the same sample, lighting, and imaging settings. The results show that TiO2 meta-superlens performs consistently better over BTG superlens in terms of imaging contrast, clarity, field of view, and resolution, which was further supported by theoretical simulation. This opens new possibilities in developing more powerful, robust, and reliable super-resolution lens and imaging systems. Keywords: super-resolution imaging; dielectric superlens; label-free imaging; titanium dioxide Citation: Dhama, R.; Yan, B.; Palego, 1. Introduction C.; Wang, Z. Super-Resolution The optical microscope is the most common imaging tool known for its simple de- Imaging by Dielectric Superlenses: sign, low cost, and great flexibility.
    [Show full text]
  • Dielectric Optical Cloak
    Dielectric Optical Cloak Jason Valentine1*, Jensen Li1*, Thomas Zentgraf1*, Guy Bartal1 and Xiang Zhang1,2 1NSF Nano-scale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA 2Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 *These authors contributed equally to this work Invisibility or cloaking has captured human’s imagination for many years. With the recent advancement of metamaterials, several theoretical proposals show cloaking of objects is possible, however, so far there is a lack of an experimental demonstration at optical frequencies. Here, we report the first experimental realization of a dielectric optical cloak. The cloak is designed using quasi-conformal mapping to conceal an object that is placed under a curved reflecting surface which imitates the reflection of a flat surface. Our cloak consists only of isotropic dielectric materials which enables broadband and low-loss invisibility at a wavelength range of 1400-1800 nm. 1 For years, cloaking devices with the ability to render objects invisible were the subject of science fiction novels while being unattainable in reality. Nevertheless, recent theories including transformation optics (TO) and conformal mapping [1-4] proposed that cloaking devices are in principle possible, given the availability of the appropriate medium. The advent of metamaterials [5-7] has provided such a medium for which the electromagnetic material properties can be tailored at will, enabling precise control over the spatial variation in the material response (electric permittivity and magnetic permeability). The first experimental demonstration of cloaking was recently achieved at microwave frequencies [8] utilizing metallic rings possessing spatially varied magnetic resonances with extreme permeabilities.
    [Show full text]
  • The Quest for the Superlens
    THE QUEST FOR THE CUBE OF METAMATERIAL consists of a three- dimensional matrix of copper wires and split rings. Microwaves with frequencies near 10 gigahertz behave in an extraordinary way in the cube, because to them the cube has a negative refractive index. The lattice spacing is 2.68 millimeters, or about one tenth of an inch. 60 SCIENTIFIC AMERICAN COPYRIGHT 2006 SCIENTIFIC AMERICAN, INC. Superlens Built from “metamaterials” with bizarre, controversial optical properties, a superlens could produce images that include details fi ner than the wavelength of light that is used By John B. Pendry and David R. Smith lmost 40 years ago Russian scientist Victor Veselago had Aan idea for a material that could turn the world of optics on its head. It could make light waves appear to fl ow backward and behave in many other counterintuitive ways. A totally new kind of lens made of the material would have almost magical attributes that would let it outperform any previously known. The catch: the material had to have a negative index of refraction (“refraction” describes how much a wave will change direction as it enters or leaves the material). All known materials had a positive value. After years of searching, Veselago failed to fi nd anything having the electromagnetic properties he sought, and his conjecture faded into obscurity. A startling advance recently resurrected Veselago’s notion. In most materials, the electromagnetic properties arise directly from the characteristics of constituent atoms and molecules. Because these constituents have a limited range of characteristics, the mil- lions of materials that we know of display only a limited palette of electromagnetic properties.
    [Show full text]
  • Molecular Scale Imaging with a Smooth Superlens
    Molecular Scale Imaging with a Smooth Superlens Pratik Chaturvedi1, Wei Wu2, VJ Logeeswaran3, Zhaoning Yu2, M. Saif Islam3, S.Y. Wang2, R. Stanley Williams2, & Nicholas Fang1* 1Department of Mechanical Science & Engineering, University of Illinois at Urbana- Champaign, 1206 W. Green St., Urbana, IL 61801, USA. 2Information & Quantum Systems Lab, Hewlett-Packard Laboratories, 1501 Page Mill Rd, MS 1123, Palo Alto, CA 94304, USA. 3Department of Electrical & Computer Engineering, Kemper Hall, University of California at Davis, One Shields Ave, Davis, CA 95616, USA. * Corresponding author Email: [email protected] RECEIVED DATE Abstract We demonstrate a smooth and low loss silver (Ag) optical superlens capable of resolving features at 1/12th of the illumination wavelength with high fidelity. This is made possible by utilizing state-of-the-art nanoimprint technology and intermediate 1 wetting layer of germanium (Ge) for the growth of flat silver films with surface roughness at sub-nanometer scales. Our measurement of the resolved lines of 30nm half-pitch shows a full-width at half-maximum better than 37nm, in excellent agreement with theoretical predictions. The development of this unique optical superlens lead promise to parallel imaging and nanofabrication in a single snapshot, a feat that are not yet available with other nanoscale imaging techniques such as atomic force microscope or scanning electron microscope. λ = 380nm 250nm The resolution of optical images has historically been constrained by the wavelength of light, a well known physical law which is termed as the diffraction limit. Conventional optical imaging is only capable of focusing the propagating components from the source. The evanescent components which carry the subwavelength information exponentially decay in a medium with positive permittivity (ε), and positive permeability (µ) and hence, are lost before making it to the image plane.
    [Show full text]
  • A Review of Anomalous Resonance, Its Associated Cloaking, and Superlensing Volume 21, Issue 4-5 (2020), P
    Comptes Rendus Physique Ross C. McPhedran and Graeme W. Milton A review of anomalous resonance, its associated cloaking, and superlensing Volume 21, issue 4-5 (2020), p. 409-423. <https://doi.org/10.5802/crphys.6> Part of the Thematic Issue: Metamaterials 1 Guest editors: Boris Gralak (CNRS, Institut Fresnel, Marseille, France) and Sébastien Guenneau (UMI2004 Abraham de Moivre, CNRS-Imperial College, London, UK) © Académie des sciences, Paris and the authors, 2020. Some rights reserved. This article is licensed under the Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/ Les Comptes Rendus. Physique sont membres du Centre Mersenne pour l’édition scientifique ouverte www.centre-mersenne.org Comptes Rendus Physique 2020, 21, nO 4-5, p. 409-423 https://doi.org/10.5802/crphys.6 Metamaterials 1 / Métamatériaux 1 A review of anomalous resonance, its associated cloaking, and superlensing Résonance anormale, invisibilité et super-resolution associée : état de l’art , a b Ross C. McPhedran¤ and Graeme W. Milton a School of Physics, The University of Sydney, Australia b Department of Mathematics, University of Utah, USA E-mails: [email protected] (R. C. McPhedran), [email protected] (G. W. Milton) Abstract. We review a selected history of anomalous resonance, cloaking due to anomalous resonance, cloaking due to complementary media, and superlensing. Résumé. Nous passons en revue quelques faits saillant de l’historique de la résonance anormale, de l’invisibi- lité associée à la résonance anormale, et celle associée aux milieux complémentaires et de la super-résolution. Keywords. Anomalous resonance, Cloaking, Superlensing.
    [Show full text]
  • Transformation Optical User-Friendly Interface for Designing Metamaterials
    Article Transformation Optical User-Friendly Interface for Designing Metamaterials Pasit Jarutatsanangkoona, and Wanchai Pijitrojanab,* Department of Electrical and Computer Engineering, Faculty of Engineering, Thammasat University, Rangsit Campus, Pathumthani 12120, Thailand E-mail: [email protected], [email protected] (Corresponding author) Abstract. Transformation optics offers a procedure to design the structures of metamaterials to find the material parameters needed in various applications. However, a methodology of a transformation optics is too complicated. To help users who are beginning to study metamaterials and transformation optics, a transformation optical user- friendly interface is developed. The interface is implemented based on the free-form touch transformation. It displays the starting space as a Cartesian grid. As the user touches and moves, the space transforms according to the direction and the intensity of the touch without inputting any equations. By combining various transformation templates, a fully arbitrary transformation can be realized. Transformation templates are created by basic functions such as the ring transformation in the invisibility cloak or the morphing of a half circle into a rectangle in the superlens. The interface provides both the input methods as well as the real-time visualization of the space making it easy and intuitive to design a metamaterial using the transformation optics. The program uses model-view-controller architecture. The connections of each class are presented in a diagram. Three examples from the touch interface are verified by the FDFD simulation. Keywords: Metamaterials, spatial transformation, transformation optics, touch interface. ENGINEERING JOURNAL Volume 23 Issue 6 Received 28 June 2019 Accepted 12 September 2019 Published 30 November 2019 Online at http://www.engj.org/ DOI:10.4186/ej.2019.23.6.225 DOI:10.4186/ej.2019.23.6.225 1.
    [Show full text]
  • Subwavelength Resolution with a Negative-Index Metamaterial Superlens Koray Aydin, Irfan Bulu, and Ekmel Ozbay
    Subwavelength resolution with a negative-index metamaterial superlens Koray Aydin, Irfan Bulu, and Ekmel Ozbay Citation: Appl. Phys. Lett. 90, 254102 (2007); doi: 10.1063/1.2750393 View online: http://dx.doi.org/10.1063/1.2750393 View Table of Contents: http://aip.scitation.org/toc/apl/90/25 Published by the American Institute of Physics Articles you may be interested in Imaging properties of a metamaterial superlens Applied Physics Letters 82, 161 (2003); 10.1063/1.1536712 Electric-field-coupled resonators for negative permittivity metamaterials Applied Physics Letters 88, 041109 (2006); 10.1063/1.2166681 Observation of negative refraction and negative phase velocity in left-handed metamaterials Applied Physics Letters 86, 124102 (2005); 10.1063/1.1888051 Rapid growth of evanescent wave by a silver superlens Applied Physics Letters 83, 5184 (2003); 10.1063/1.1636250 Microwave transmission through a two-dimensional, isotropic, left-handed metamaterial Applied Physics Letters 78, 489 (2001); 10.1063/1.1343489 Limitations on subdiffraction imaging with a negative refractive index slab Applied Physics Letters 82, 1506 (2003); 10.1063/1.1554779 APPLIED PHYSICS LETTERS 90, 254102 ͑2007͒ Subwavelength resolution with a negative-index metamaterial superlens ͒ Koray Aydin,a Irfan Bulu, and Ekmel Ozbay Nanotechnology Research Center-NANOTAM, Bilkent University, Bilkent, 06800 Ankara, Turkey; Department of Physics, Bilkent University, Bilkent, 06800 Ankara, Turkey; and Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, 06800 Ankara, Turkey ͑Received 8 March 2007; accepted 26 May 2007; published online 19 June 2007͒ Negative-index metamaterials are candidates for imaging objects with sizes smaller than a half-wavelength.
    [Show full text]
  • Amplifying Evanescent Waves by Dispersion- Induced Plasmons: Defying the Materials Limitation of Superlens
    Amplifying Evanescent Waves by Dispersion- induced Plasmons: Defying the Materials Limitation of Superlens Tie-Jun Huang, Li-Zheng Yin, Jin Zhao, Chao-Hai Du, Pu-Kun Liu* State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronics, Peking University, Beijing, 100871, China *Correspondence to [email protected] Breaking the diffraction limit is always an appealing topic due to the urge for a better imaging resolution in almost all areas. As an effective solution, the superlens based on the plasmonic effect can resonantly amplify evanescent waves, and achieve subwavelength resolution. However, the natural plasmonic materials, within their limited choices, usually have inherit high losses and are only available from the infrared to visible wavelengths. In this work, we theoretically and experimentally demonstrate that the arbitrary materials, even air, can be used to enhance evanescent waves and build low loss superlens with at the desired frequency. The operating mechanisms reside in the dispersion-induced effective plasmons in a bounded waveguide structure. Based on this, we construct the hyperbolic metamaterials and experimentally verified its validity in the microwave range by the directional propagation and imaging with a resolution of 0.087λ. We also demonstrate that the imaging potential can be extended to terahertz and infrared bands. The proposed method not only break the conventional barriers of plasmon- based lenses, but also bring possibilities in applications based on the enhancing evanescent waves from microwave to infrard wavelengths, such as ultrasensitive optics, spontaneous emission, light beam steering. 1 Introduction Imaging with the unlimited resolution has been an intriguing dream of scientists for a few centuries.
    [Show full text]
  • Imaging Properties of a Metamaterial Superlens
    APPLIED PHYSICS LETTERS VOLUME 82, NUMBER 2 13 JANUARY 2003 Imaging properties of a metamaterial superlens Nicholas Fang and Xiang Zhanga) Department of Mechanical and Aerospace Engineering, University of California at Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095 ͑Received 24 September 2002; accepted 18 November 2002͒ The subwavelength imaging quality of a metamaterial superlens is studied numerically in the wave vector domain. Examples of image compression and magnification are given and resolution limits are discussed. A minimal resolution of ␭/6 is obtained using a 36 nm silver film at 364 nm wavelength. Simulation also reveals that the power flux is no longer a good measure to determine the focal plane of superlens due to the elevated field strength at exit side of the metamaterial slab. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1536712͔ Metamaterials have opened an exciting gateway to cre- 2a; the separation from the current sources to the slab is ate unprecedented physical properties and functionality unat- defined as the object distance, u. The electromagnetic field tainable from naturally existing materials. The ‘‘atoms’’ and due to TM sources J(r)ϭzˆI␦(rϪrЈ), located at rЈϭ(x ‘‘molecules’’ in metamaterials can be tailored in shape and ϭϮa,zϭϪu), travels through the metalens of thickness d size; the lattice constant and interatomic interaction can be ␧ ␮ with designed properties M and M , and reaches medium 2 artificially tuned, and ‘‘defects’’ can be designed and placed where the images are formed at a distance v to the right-hand at desired locations. Pioneering work on strongly modulated side of the lens.
    [Show full text]
  • Green's Function for Metamaterial Superlens: Evanescent Wave in The
    Green's function for metamaterial superlens: Evanescent wave in the image Wei Li∗ and XunYa Jiang† State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China We develop a new method to calculate the evanescent wave, the subdivided evanescent waves (SEWs), and the radiative wave, which can be obtained by separating the global field of the image of metamaterial superlens. The method is based on Green's function, and it can be applied in other linear systems. This study could help us to investigate the effect of evanescent wave on metamaterial superlens directly, and give us a new way to design new devices. PACS number: 42.25.-p; 42.15.Eq Keywords: metamaterial; superlens; evanescent wave; Green's function ∗ Email: [email protected] † Email: [email protected] Fax: +86-21-52419931 1 I. INTRODUCTION Early in 1968, Veselago [1] predicted that a new type of artificial metamaterial, which possesses simultaneously negative permittivity and permeability, could function as a lens to focus electromagnetic waves. This research direction was promoted by Pendry’s work [2, 3] and other latter works [4–26]. They show that with such metamaterial lens, not only radiative waves but also evanescent waves, can be collected at its image, so the lens could be a superlens which can break through or overcome the diffraction limit of conventional imaging system. This beyond-limit property gives us a new window to design devices. It is well-known that evanescent wave plays an important role in the beyond-limit property of the metamaterial superlens.
    [Show full text]