Optical metamaterials opened a whole new paradigm in physics and engineering by enabling new optical properties and devices not achievable using natural materials. 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. Threedimensional 3d optical metamaterials have come into focus recently, including the realization of negative refraction by using layered semiconductor metamaterials and a 3d magnetic. Box 1527, 71110 heraklion, crete greece, and department of materials science and technology, university of crete, heraklion, greece. In 2000, an artificially structured composite was shown to exhibit a negative index of refraction over a band of microwave frequencies 1. Ultra lowloss, isotropic optical negativeindex metamaterial. 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. Refraction of light rays by material with negative. Indeed, it is now established that negative refraction can occur in materials displaying anisotropy, such as calcite, and in two or threedimensionally structured mate. Negative index metamaterials based on two dimensional. Osa metamaterials with gradient negative index of refraction.
The theory underpinning this field treats electromagnetic composites using homogenization and effective medium theory emt. Such behavior results from the plasmon resonance in the pairs of nanorods for both the electric and the magnetic components. Experimental results revealing new phenomena and potential applications for these artificial materials, more recently termed metamaterials mms, have provided. Negative values of the material parameters can be achieved in composite media near resonances, which implies very dispersive properties.
Metamaterials with negative refraction may lead to the development of a superlens capable of. 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. Materials with negative refractive index do not exist in nature, but there are attempts to produce composite materials with this property. Structured surfaces for generation of negative index of. Other fundamental phenomena, such as cherenkov radiation and the doppler effect, are also reversed in negative index materials.
For pairs of metal rods, a negative refractive index has been observed at 1. Pdf metamaterials with gradient negative index of refraction. Specially designed metaldielectric composites can have a negative refractive index in the optical range. The index of refraction of the first and second media is denoted by n 1 and n 2 respectively, and. Metamaterials with negative refractive index at optical. In addition, we also observed optical zeroindex at 1. A doubleperiodic array of pairs of parallel gold nanorods is shown to have a negative refractive index in the optical range. Springer series in materials science 98 physics of negative. Optical negative index metamaterials by xuhuai zhang. 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. Recently negative index materials nims and photonic crystals pcs are getting more and more attention because of its extraordinary optical properties like near.
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. 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. Alldielectric metaoptics and nonlinear nanophotonics. Resolving the wave vector in negative refractive index media. Negative index of refraction in optical metamaterials article pdf available in optics letters 3024. 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. Negative refraction at visible frequencies science. Metamaterials with negative refraction may lead to. Introduction and motivation meta materials is a general term referring to manmade composites which have the desirable properties unavailable in the naturally occurring materials.
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. Physics and applications of negative refractive index materials. Negative index of refraction of crossbar metamaterial jordan claspell department of physics bachelor of science the purpose of this project is twofold. 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. Note that the parallel component of wave vector is always preserved in transmission, but that energy flow is opposite to the wave vector. Osa negative index of refraction in optical metamaterials. By providing access to new realms of material response, mms have and will continue to impact the fields of physics, materials science, engineering, optics.
However, artificially designed materials metamaterials can act as nims. Unlike the conventional negative index material designs, such as the splitring resonator type design19 and. 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. Negative effective permeability and lefthanded materials at optical frequencies.
The refractive index is one of the most fundamental characteristics of light propagation in materials. Pdf a doubleperiodic array of pairs of parallel gold nanorods is shown to have a negative refractive index in the optical range. A3944 november 2007 with 768 reads how we measure reads. Pdf negative index of refraction in optical metamaterials vladimir drachev academia. Optical negativeindex metamaterials purdue engineering. Moreover, such bulk metamaterials can support propagating waves with large wave vectors.
Specifically, it is shown that arrays of single and paired nanorods can provide such negative refraction. Despite the unambiguous negative refraction results, the bulk fishnet structure only worked for a particular polarization. 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. 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. The contributors to this book prepared their chapters coming from very diversi. 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. Economou3 1department of physics and ames laboratory, iowa state university, ames, iowa, usa 2ieslforth, p. Metamaterials with negative refraction may lead to the. 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. Although negative permittivity is quite common in metals at optical wavelengths, it is very challenging to find natural. 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. Here we report a 3d optical metamaterial having negative refractive index with a very high figure of merit of 3.
Wiremesh structures as low frequency negative dielectrics 458 2. This is described by snells law of refraction, n 1 sin. The implementation of negativerefraction metamaterials at optical. Shalaev, wenshan cai, uday chettiar, hsiaokuan yuan, andrey k. Negative refractive index metamaterials infrared nanooptics of. 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. However, it is challenging to realize negative refractive index at such high frequency range using srr structures. Numerous applications exist for nims in every spectral range, from microwave to optical. Ii smolyaninov, yj hung, and cc davis, pdfphysics 0610230. Among the fascinating properties is a negative refractive index. The negative refractive index in the optical range. Negative index of refraction in optical metamaterials purdue.
We are interested in making materials that have a negative index of refraction. Physics of negative refraction and negative index materials. Recently, many groups have fabricated samples and observed1924 negative l in the terahertz region. Negative refraction at optical frequencies in nonmagnetic. 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. We are developing ways to make optical metamaterials. Chapter 1 negative refractive index metamaterials in optics. Negative refractive index in optics of metaldielectric. Moreover, it can readily be probed from free space, making it functional for optical devices. Negative refractive index in artificial metamaterials arxiv. The imaginary part of the refractive index also shows resonant behavior and it is large near the resonance. We demonstrate that arrays of split ring resonators srr can have negative refractive index at optical frequencies 1.
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. A slot waveguide is used to model a fast charged particle. Pdf negative index of refraction in optical metamaterials. Optical magnetism and negative refraction in plasmonic. Negative refractive index and metamaterials metamaterial. It is defined as, where c is the speed of light in vacuum and v is the phase velocity of light in the medium. Negative refraction and focusing anan fang1,thomas koschny1,2 and costas m.
Optical negative refraction in bulk metamaterials of nanowires. 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 determines how much the path of light is bent, or refracted, when entering a material. In figure 5, we present results for srrs that give a negative l at 100 thz. Negative indices were achieved with the use of an ultrathin au. The refractive index is retrieved from direct phase and amplitude measurements for transmission and reflection, which are all in. Hence in a negative refractive index material, light makes a negative angle. Negativeindex materials nims have a negative refractive index so that electromagnetic waves in such media propagate in a direction opposite to the. Metamaterials with gradient negative index of refraction article pdf available in journal of the optical society of america a 2410.
Reversed cherenkov radiation in left handed meta material. Specially designed metal dielectric composites can have a negative refractive index in the optical range. Ii smolyaninov, yj hung, and cc davis, pdfphysics0610230. One of those unusual properties is the ability to reverse, for the first time, snells law of refraction. Zeroindex metamaterials open new possibilities for. The prismlike metamaterial is used to filter the reversed cherenkov wave. Index terms left handed materials, metamaterials, nanoparticle plasmon resonance, negative refractive index. Nanofabricated photonic materials offer opportunities for crafting the propagation and dispersion of light in matter. Negative index of refraction in optical metamaterials osa. This book is devoted to the description of metamaterials, their origins and physical principles, their electromagnetic and optical properties, as well as to. Negative refractive index metamaterials sciencedirect.
Th e refractive index is one of the most fundamental characteristics of light propagation in materials. 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. One of the most fascinating examples of such structures is negativeindex metamaterials nims. Note a rather high transmittance of 25% and relatively low absorption of 10%. A singlelayer wideangle negativeindex metamaterial at visible frequencies. Optical negativeindex metamaterials purdue university. Optical negativeindex metamaterials nature photonics. We discuss optical constants in artificial metamaterials showing negative magnetic permeability and electric permittivity and suggest a simple formula for the. 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. We show that the negative refraction originate from the 3d chiral properties of the bilayer cross wires.
Materials with negative magnetic permeability 463 2. 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. Negative index of refraction in optical metamaterials. 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.
This thesis discusses negative index metamaterials nims that exhibit negative refraction. An optical metamaterial is composed of elements that are smaller than the wavelength of light, but that can interact with light in interesting ways. Such behavior results from the plasmon resonance in the pairs of nanorods for both the electric and the magnetic components of light. This includes a negative index of refraction, invisibility cloaking, giant chirality, etc. No naturally occurring material that we know of has this property, but it could be achieved in an metamaterial. 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. Other fundamental phenomena, such as cherenkov radiation and the doppler effect, are also reversed in negativeindex materials. Preface to optical waves in crystals, electron waves in heterostructures, and guided waves in. Negative refractive index and metamaterials free download as powerpoint presentation. Threedimensional optical metamaterial with a negative. One class of metamaterials, with a refraction index of zero pdf, was first created in 20 and quickly caught the interest of scientists because of the materials unique properties. This new class of negativeindex materials is relatively easy to fabricate on the nanoscale and opens new opportunities for designing negative refraction in optics. These metamaterials use different parameters to achieve a negative index of refraction in materials that are not electromagnetic.
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