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There are
many definitions of metamaterials, which highlight various aspects of this
concept.
Metamaterial
is an arrangement of artificial structural elements, designed to achieve
advantageous and unusual electromagnetic properties.
Even
such a flexible definition is incomplete on the one hand, and too strict, on
the other. It is helpful to draw the following analogy: Metamaterial is
composed of its elements in the same sense as matter consists of atoms. But
these structural elements themselves are made of conventional materials, i.e.,
finally, of normal atoms. Accordingly, metamaterial represents the next level
of structural organization of matter.
Detailed
discussions of the metamaterial concept can be found, for example, in following
reviews:
- Ari
Sihvola, "Metamaterials in electromagnetics," Metamaterials, 1(1),
pp. 2-11, 2007 (access to "Metamaterials")
- Mikhail
Lapine and Sergei Tretyakov, "Contemporary notes on metamaterials," IET Proc.
Microwaves, Antennas & Propagation, 1(1), pp. 3-11, 2007 (view article at IET) or (view article at IEEE Xplore); see also (NOTE)
The concept of material implies homogeneity, and, if a metamaterial is a periodical structure, the lattice constants should be considerably smaller than the wavelength. This distinguishes metamaterials from photonic (electromagnetic) crystals and frequency-selective surfaces, whose useful and unusual electromagnetic properties originate from the periodicity of their structure. In contrast to photonic crystals, metamaterials can be realized as random mixtures of "artificial molecules".
Metamaterials
are often associated with negative refraction, although this is only one of the possible unusual electromagnetic phenomena. Large collection of historical
references on that subject is offered on the webpage
of Alexander Moroz.
Selected
sub-areas of metamaterial research are briefly outlined here.
Useful reading:
1. Microwave Metamaterials and Applications: Current Status of the Experimental and Theoretical Developments by Prof. George V. Eleftheriades, Eleftheriades_Rome_Oct2007.pdf (3.02 MB 22.11.2007 13:36) , Plenary talk at Metamaterials 2007 Congress, September 2007, Rome, Italy
2. "Optical Metamaterials and Applications" Rome_Plenary_pdf1.pdf (21.02 MB) by Prof. Vladimir M. Shalaev from the School of Electrical & Computer Engineering, Purdue University, USA, Plenary talk at Metamaterials 2007 Congress, September 2007, Rome, Italy.
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