Negative refractive index in optics of metaldielectric. Optical negativeindex metamaterials purdue university. It is defined as, where c is the speed of light in vacuum and v is the phase velocity of light in the medium. Although negative permittivity is quite common in metals at optical wavelengths, it is very challenging to find natural. We show that the negative refraction originate from the 3d chiral properties of the bilayer cross wires. The imaginary part of the refractive index also shows resonant behavior and it is large near the resonance. Metamaterials with negative refractive index at optical. Shalaev, wenshan cai, uday chettiar, hsiaokuan yuan, andrey k. Threedimensional optical metamaterial with a negative. Refraction of light rays by material with negative. However, artificially designed materials metamaterials can act as nims. A3944 november 2007 with 768 reads how we measure reads. Metamaterials with gradient negative index of refraction article pdf available in journal of the optical society of america a 2410.
No naturally occurring material that we know of has this property, but it could be achieved in an metamaterial. Physics of negative refraction and negative index materials. In optics, the refractive index or index of refraction of a material is a dimensionless number that describes how fast light travels through the material. The contributors to this book prepared their chapters coming from very diversi. Metamaterials with negative refraction may lead to the. We demonstrate an experimental realization of a twodimensional negativeindex material in the bluegreen region of the visible spectrum, substantiated by direct geometric visualization of negative refraction. Note a rather high transmittance of 25% and relatively low absorption of 10%. Springer series in materials science 98 physics of negative. Optical negative refraction in bulk metamaterials of nanowires. Optical negativeindex metamaterials purdue engineering. Negative index materials nims have a negative refractive index so that electromagnetic waves in such media propagate in a direction opposite to the flow of energy, which is indeed unusual and counterintuitive. Negative index of refraction of crossbar metamaterial jordan claspell department of physics bachelor of science the purpose of this project is twofold.
Numerous applications exist for nims in every spectral range, from microwave to optical. Preface to optical waves in crystals, electron waves in heterostructures, and guided waves in. Wiremesh structures as low frequency negative dielectrics 458 2. In 2000, it was shown theoretically that several photonic crystal configurations could exhibit the same types of optical phenomena predicted for negative index materials, including negative refraction and imaging by a planar surface. Ii smolyaninov, yj hung, and cc davis, pdfphysics0610230. The negative refractive index in the optical range. Other fundamental phenomena, such as cherenkov radiation and the doppler effect, are also reversed in negative index materials. In essence these negative index metamaterials were noted for having the ability to reverse many of the physical properties that govern the behavior of ordinary optical materials. Reversed cherenkov radiation in left handed meta material. Optical magnetism and negative refraction in plasmonic. A singlelayer wideangle negativeindex metamaterial at visible frequencies. Negative index metamaterials based on two dimensional.
Negativeindex materials nims have a negative refractive index so that electromagnetic waves in such media propagate in a direction opposite to the. A slot waveguide is used to model a fast charged particle. A doubleperiodic array of pairs of parallel gold nanorods is shown to have a negative refractive index in the optical range. Moreover, it can readily be probed from free space, making it functional for optical devices. For pairs of metal rods, a negative refractive index has been observed at 1. Indeed, it is now established that negative refraction can occur in materials displaying anisotropy, such as calcite, and in two or threedimensionally structured mate. Pdf a doubleperiodic array of pairs of parallel gold nanorods is shown to have a negative refractive index in the optical range. Metamaterials with negative refraction may lead to. Because the dielectric response in this meta material does not require any resonance, the negative refraction has low loss and occurs in a broad spectral range, for all incident angles, making it an intrinsic optical response of the underlying meta materials. This new class of negativeindex materials is relatively easy to fabricate on the nanoscale and opens new opportunities for designing negative refraction in optics.
One of the most fascinating examples of such structures is negativeindex metamaterials nims. Th e refractive index is one of the most fundamental characteristics of light propagation in materials. Specifically, it is shown that arrays of single and paired nanorods can provide such negative refraction. Pdf negative index of refraction in optical metamaterials vladimir drachev academia. Optical metamaterials opened a whole new paradigm in physics and engineering by enabling new optical properties and devices not achievable using natural materials. In 2001 negative refraction was first experimentally demonstrated by american physicist robert shelby and his colleagues at microwave wavelengths, and the phenomenon was subsequently extended to optical wavelengths. In 2000, an artificially structured composite was shown to exhibit a negative index of refraction over a band of microwave frequencies 1. A thin metal film pierced with holes of appropriate size or spacing between them can be used as a. The prismlike metamaterial is used to filter the reversed cherenkov wave. Negative refraction at optical frequencies in nonmagnetic. The implementation of negativerefraction metamaterials at optical.
Negativeindex materials nims have a negative refractive index so that electromagnetic waves in such media propagate in a direction opposite to the flow of energy, which is indeed unusual and counterintuitive. Soukoulis1,3 1ames laboratory and department of physics and astronomy, iowa state university, ames, iowa 50011, usa 2institute of optical fiber commun. The refractive index is retrieved from direct phase and amplitude measurements for transmission and reflection, which are all in. Negative effective permeability and lefthanded materials at optical frequencies. Metamaterials with negative refraction may lead to the development of a superlens capable of. Optical negative index metamaterials by xuhuai zhang. Physics and applications of negative refractive index materials. Recent advances in nanofabrication have led to the demonstration of a novel class of optical materialsmetamaterialsthat are artificially engineered structures with electromagnetic properties unattainable in nature.
The refractive index determines how much the path of light is bent, or refracted, when entering a material. Aug 11, 2008 threedimensional 3d optical metamaterials have come into focus recently, including the realization of negative refraction by using layered semiconductor metamaterials and a 3d magnetic. Osa negative index of refraction in optical metamaterials. Strong optical magnetism that gives rise to negative permeability is highly sought after, for its combination with the negative permittivity can lead to negative refractive index metamaterials nims in the optical frequency regime. The refractive index is one of the most fundamental characteristics of light propagation in materials. Negative refractive index metamaterials sciencedirect. One of those unusual properties is the ability to reverse, for the first time, snells law of refraction. Index terms left handed materials, metamaterials, nanoparticle plasmon resonance, negative refractive index. Despite the unambiguous negative refraction results, the bulk fishnet structure only worked for a particular polarization. Other fundamental phenomena, such as cherenkov radiation and the doppler effect, are also reversed in negativeindex materials.
The theory underpinning this field treats electromagnetic composites using homogenization and effective medium theory emt. This thesis discusses negative index metamaterials nims that exhibit negative refraction. Negative refraction at visible frequencies science. The index of refraction of the first and second media is denoted by n 1 and n 2 respectively, and. A slab of the negative refractive index metamaterial has a focal length that can be tuned by changing the gradient of the negative refractive index. Recently negative index materials nims and photonic crystals pcs are getting more and more attention because of its extraordinary optical properties like near. Our calculations reveal that the electric fields of radiation interact strongly with even symmetric srr at optical frequencies as the size of the srr becomes of the order of the wavelength lambda 3 for practicably realizable structures. We demonstrate that arrays of split ring resonators srr can have negative refractive index at optical frequencies 1. This is described by snells law of refraction, n 1 sin. Optical negativeindex metamaterials nature photonics. Negative refractive index and metamaterials metamaterial. Alldielectric metaoptics and nonlinear nanophotonics.
Such behavior results from the plasmon resonance in the pairs of nanorods for both the electric and the magnetic components of light. Sep 10, 2001 recently, electromagnetic materials with negative permittivity and permeability values sometime called media with negative refraction index have been given much attention in the literature. Negative index of refraction in optical metamaterials. Structured surfaces for generation of negative index of. Recently, many groups have fabricated samples and observed1924 negative l in the terahertz region. Introduction and motivation meta materials is a general term referring to manmade composites which have the desirable properties unavailable in the naturally occurring materials. Unlike the conventional negative index material designs, such as the splitring resonator type design19 and. Hence in a negative refractive index material, light makes a negative angle. We discuss optical constants in artificial metamaterials showing negative magnetic permeability and electric permittivity and suggest a simple formula for the. An optical metamaterial is composed of elements that are smaller than the wavelength of light, but that can interact with light in interesting ways. Negative indices were achieved with the use of an ultrathin au. With the help of the demonstration, it can be seen that for, a flat plate can focus light rays, and that if, the image of the point source is a point.
Pdf negative index of refraction in optical metamaterials. Implementations of negativerefraction metamaterials at optical frequencies unusual propagation phenomena in metallic waveguides partially filled with negativerefractiveindex metamaterials metamaterials in which the refractive index and the underlying group velocity are both negative. Because the dielectric response in this metamaterial does not require any resonance, the negative refraction has low loss and occurs in a broad spectral range, for all incident angles, making it an intrinsic optical response of the underlying metamaterials. Box 1527, 71110 heraklion, crete greece, and department of materials science and technology, university of crete, heraklion, greece. This book is devoted to the description of metamaterials, their origins and physical principles, their electromagnetic and optical properties, as well as to.
Nanofabricated photonic materials offer opportunities for crafting the propagation and dispersion of light in matter. Furthermore, a new design for elastic metamaterials that can behave either as liquids or solids over a limited frequency range may enable new applications based on the control of acoustic, elastic and seismic waves. In addition, we also observed optical zeroindex at 1. Negative values of the material parameters can be achieved in composite media near resonances, which implies very dispersive properties. We propose a new metamaterial with a gradient negative index of refraction, which can focus a collimated beam of light coming from a distant object. Osa metamaterials with gradient negative index of refraction. Pdf metamaterials with gradient negative index of refraction. Note that the parallel component of wave vector is always preserved in transmission, but that energy flow is opposite to the wave vector. Materials with negative magnetic permeability 463 2. Negative index of refraction in optical metamaterials article pdf available in optics letters 3024. Negative refractive index in artificial metamaterials arxiv.
We are developing ways to make optical metamaterials. Specially designed metaldielectric composites can have a negative refractive index in the optical range. We are interested in making materials that have a negative index of refraction. Resolving the wave vector in negative refractive index media. Zeroindex metamaterials open new possibilities for. Negative index of refraction of crossbar metamaterial. This demonstration of a previously unexploited electromagnetic em property proved the importance of engineered materials and has resulted in an extraordinary amount of continued development by scientists working in optics, electromagnetism, physics. Here we report a 3d optical metamaterial having negative refractive index with a very high figure of merit of 3. These metamaterials use different parameters to achieve a negative index of refraction in materials that are not electromagnetic. Negative index of refraction in optical metamaterials purdue. Negative refractive index metamaterials infrared nanooptics of.
One of the most fundamental notions in optics is that of refractive index, which gives the factor by which the phase velocity of light is decreased in a material compared to vacuum conditions. Materials with negative refractive index do not exist in nature, but there are attempts to produce composite materials with this property. Ultra lowloss, isotropic optical negativeindex metamaterial. Negative index of refraction in optical metamaterials osa. By providing access to new realms of material response, mms have and will continue to impact the fields of physics, materials science, engineering, optics. Many such important phenomena are the manifestation of optical magnetism, predicted and observed in specifically designed artificial subwavelength structures that allow a strong magnetic response, even when such structures are made of nonmagnetic materials. Such behavior results from the plasmon resonance in the pairs of nanorods for both the electric and the magnetic components. Negative refraction and focusing anan fang1,thomas koschny1,2 and costas m. Experimental results revealing new phenomena and potential applications for these artificial materials, more recently termed metamaterials mms, have provided. In figure 5, we present results for srrs that give a negative l at 100 thz. Ii smolyaninov, yj hung, and cc davis, pdfphysics 0610230.
Negative refractive index due to chirality jiangfeng zhou,1 jianfeng dong,2,1 bingnan wang,1 thomas koschny,1,3 maria kafesaki,3 and costas m. Economou3 1department of physics and ames laboratory, iowa state university, ames, iowa, usa 2ieslforth, p. Moreover, such bulk metamaterials can support propagating waves with large wave vectors. Negative refractive index and metamaterials free download as powerpoint presentation. Specially designed metal dielectric composites can have a negative refractive index in the optical range.
Threedimensional 3d optical metamaterials have come into focus recently, including the realization of negative refraction by using layered semiconductor metamaterials and a 3d magnetic. However, it is challenging to realize negative refractive index at such high frequency range using srr structures. Among the fascinating properties is a negative refractive index. The main challenge in making a negative index metamaterial nim is that both the effective dielectric permittivity eff and magnetic permeability eff must be negative 1.
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