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Metamaterials four to work for visible light
January 05, 2007
AMES, Iowa - For the first time ever, researchers at the U.S. Department of Energy's Ames Laboratory have developed a material with a negative refractive index for visible light. Ames Laboratory senior physicist Costas Soukoulis, working with colleagues in Karlsruhe, Germany, designed a silver-based, mesh-like material that marks the latest advance in the rapidly evolving field of metamaterials, materials that could lead to a wide range of new applications as varied as ultrahigh-resolution imaging systems and cloaking devices. The discovery, detailed in the Jan. 5 issue of Science and the Jan. 1 issue of Optic Letters, and noted in the journal Nature, marks a significant step forward from existing metamaterials that operate in the microwave or far infrared - but still invisible -regions of the spectrum. Those materials, announced this past summer, were heralded as the first step in creating an invisibility cloak.
Metamaterials, also known as left-handed materials, are exotic, artificially created materials that provide optical properties not found in natural materials. Natural materials refract light, or electromagnetic radiation, to the right of the incident beam at different angles and speeds. However, metamaterials make it possible to refract light to the left, or at a negative angle. This backward-bending characteristic provides scientists the ability to control light similar to the way they use semiconductors to control electricity, which opens a wide range of potential applications.
"Left-handed materials may one day lead to the development of a type of flat superlens that operates in the visible spectrum," said Soukoulis, who is also an Iowa State University Distinguished Professor of Liberal Arts and Sciences. "Such a lens would offer superior resolution over conventional technology, capturing details much smaller than one wavelength of light to vastly improve imaging for materials or biomedical applications," such as giving researchers the power to see inside a human cell or diagnose disease in a baby still in the womb.
The challenge that Soukoulis and other scientists who work with metamaterials face is to fabricate them so that they refract light at ever smaller wavelengths. The "fishnet" design developed by Soukoulis' group and produced by researchers Stefan Linden and Martin Wegener at the University of Karlsruhe was made by etching an array of holes into layers of silver and magnesium fluoride on a glass substrate. The holes are roughly 100 nanometers wide. For some perspective, a human hair is about 100,000 nanometers in diameter.
"We have fabricated for the first time a negative-index metamaterial with a refractive index of -0.6 at the red end of the visible spectrum (wavelength 780 nm)," said Soukoulis. "This is the smallest wavelength obtained so far."
While the silver used in the fishnet material offers less resistance when subjected to electromagnetic radiation than the gold used in earlier materials, energy loss is still a major limiting factor. The difficulties in manufacturing materials at such a small scale also limit the attempts to harness light at ever smaller wavelengths.
"Right now, the materials we can build at THz and optical wavelengths operate in only one direction," Soukoulis said, "but we've still come a long ways in the six years since negative-index materials were first demonstrated."
"However, for applications to come within reach, several goals need to be achieved," he added. "First, reduction of losses by using crystalline metals and/or by introducing optically amplifying materials; developing three-dimensional isotropic designs rather than planar structures; and finding ways of mass producing large-area structures."
DOE/Ames Laboratory
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New 'broadband' cloaking technology simple to manufacture Researchers have created a new type of invisibility cloak that is simpler than previous designs and works for all colors of the visible spectrum, making it possible to cloak larger objects than before and possibly leading to practical applications in "transformation optics."
Blurring the Line Between Magic and Science: Berkeley Researchers Create an 'Invisibility Cloak' The great science fiction writer Arthur C. Clarke famously noted the similarities between advanced technology and magic. This summer on the big screen, the young wizard Harry Potter will once again don his magic invisibility cloak and disappear. More Metamaterials Current Events and Metamaterials News Articles
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Metamaterials: Critique and Alternatives
by Benedikt A. Munk (Author)
A Convincing and Controversial Alternative Explanation of Metamaterials with a Negative Index of Refraction In a book that will generate both support and controversy, one of the world's foremost authorities on periodic structures addresses several of the current fashions in antenna design—most specifically, the popular subject of double negative metamaterials. Professor Munk provides a comprehensive theoretical electromagnetic investigation of the issues and concludes that many of the phenomena claimed by researchers may be impossible. While denying the existence of negative refraction, the author provides convincing alternative explanations for some of the experimental examples in the literature. Although the debate on this subject is just beginning, Professor Munk...
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Waves in Metamaterials
by Laszlo Solymar (Author), Ekaterina Shamonina (Author)
Metamaterials is a young subject born in the 21st century. It is concerned with artificial materials which can have electrical and magnetic properties difficult or impossible to find in nature. The building blocks in most cases are resonant elements much smaller than the wavelength of the electromagnetic wave. The book offers a comprehensive treatment of all aspects of research in this field at a level that should appeal to final year undergraduates in physics or in electrical and electronic engineering. The mathematics is kept at a minimum; the aim is to explain the physics in simple terms and enumerate the major advances. It can be profitably read by graduate and post-graduate students in order to find out what has been done in the field outside their speciality, and by experts who may...
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Metamaterials with Negative Parameters: Theory, Design and Microwave Applications (Wiley Series in Microwave and Optical Engineering)
by Ricardo Marqués (Author), Ferran Martín (Author), Mario Sorolla (Author)
The first general textbook to offer a complete overview of metamaterial theory and its microwave applications Metamaterials with Negative Parameters represents the only unified treatment of metamaterials available in one convenient book. Devoted mainly to metamaterials that can be characterized by a negative effective permittivity and/or permeability, the book includes a wide overview of the most important topics, scientific fundamentals, and technical applications of metamaterials. Chapter coverage includes: the electrodynamics of left-handed media, synthesis of bulk metamaterials, synthesis of metamaterials in planar technology, microwave applications of metamaterial concepts, and advanced and related topics, includingSRR- and CSRR-based admittance surfaces, magneto-...
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Metamaterials Handbook - Two Volume Slipcase Set
by Filippo Capolino (Author)
The study of artificial electromagnetic materials, or metamaterials, breaks down the traditional frontiers to combine disciplines such as physics and microfabrication, electromagnetic theory and computational methods, optics and microwaves, and nanotechnology and nanochemistry.
With their unique physical properties and unusual combination of microscopic and nanoscopic structures, metamaterials have application potential in a wide range of fields, from electronics and telecommunications to sensing, medical instrumentation, and data storage. However, the strategic objectives of metamaterial development require close cooperation between the many subareas of the field and cross-fertilization of the research from each.
A superior reference for...
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Electrodynamics of Metamaterials
by Vladimir M. Shalaev (Author), Audrey K. Sarychev (Author)
Light is in a sense "one-handed" when interacting with atoms of conventional materials. This is because out of the two field components of light, electric and magnetic, only the electric "hand" efficiently probes the atoms of a material, whereas the magnetic component remains relatively unused because the interaction of atoms with the magnetic field component of light is normally weak. Metamaterials, i.e. artificial materials with rationally designed properties, can enable the coupling of both of the field components of light to meta-atoms, enabling entirely new optical properties and exciting applications with such "two-handed" light. Among the fascinating properties is a negative refractive index. The refractive index is one of the most fundamental characteristics of light propagation...
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Electromagnetic Metamaterials: Physics and Engineering Explorations
by Nader Engheta (Editor), Richard W Ziolkowski (Editor)
Leading experts explore the exotic properties and exciting applications of electromagnetic metamaterials Metamaterials: Physics and Engineering Explorations gives readers a clearly written, richly illustrated introduction to the most recent research developments in the area of electromagnetic metamaterials. It explores the fundamental physics, the designs, and the engineering aspects, and points to a myriad of exciting potential applications. The editors, acknowledged leaders in the field of metamaterials, have invited a group of leading researchers to present both their own findings and the full array of state-of-the-art applications for antennas, waveguides, devices, and components. Following a brief overview of the history of artificial materials, the publication...
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FDTD Modeling of Metamaterials: Theory and Applications
by Yang Hao (Author), Raj Mittra (Author)
Artificial metamaterials have made a huge splash in antenna, microwave, and optics engineering thanks to their extraordinary electromagnetic properties. And now, modeling their unique characteristics and behaviors in electromagnetic systems just got easier. This one-stop resource gives engineers powerful finite-difference time-domain (FDTD) techniques for modeling metamaterials, complete with applications and time-saving sample FDTD scripts. This comprehensive volume provides how-to guidance in a wide range of areas that are critical to antenna design, from computing dispersion diagrams and verifying left-handedness...to characterizing the interface of metamaterial slabs. The book also reviews electromagnetic metamaterial basics and FDTD essentials, providing the foundation needed to...
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Optical Metamaterials: Fundamentals and Applications
by Wenshan Cai (Author), Vladimir Shalaev (Author)
Metamaterials—artificially structured materials with engineered electromagnetic properties—have enabled unprecedented flexibility in manipulating electromagnetic waves and producing new functionalities. This book details recent advances in the study of optical metamaterials, ranging from fundamental aspects to up-to-date implementations, in one unified treatment. Important recent developments and applications such as superlens and cloaking devices are also treated in detail and made understandable. The planned monograph can serve as a very timely book for both newcomers and advanced researchers in this extremely rapid evolving field.
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Metamaterials: Theory, Design, and Applications
by Tie Jun Cui (Editor), David R. Smith (Editor), Ruopeng Liu (Editor)
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,...
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Applications of Metamaterials (Metamaterials Handbook)
by Filippo Capolino (Author)
This book uses the first volume’s exploration of theory, basic properties, and modeling topics to develop readers’ understanding of applications and devices that are based on artificial materials. It explores a wide range of applications in fields including electronics, telecommunications, sensing, medical instrumentation, and data storage. The text also includes a practical user’s guide and explores key areas in which artificial materials have developed. It includes experts’ perspectives on current and future applications of metamaterials, to present a well-rounded view on state-of-the-art technologies.
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