In electromagnetism (covering areas like optics and photonics), a meta material (or metamaterial) is an object that gains its (electromagnetic) material properties from its structure rather than inheriting them directly from the materials it is composed of. This term is particularly used when the resulting properties have not been found for naturally formed substances. Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ... See also list of optical topics. ... Photonics is the science and technology of generating and controlling light, and, in particular, using light to carry information. ...

Metamaterials are often made up of a collection of objects whose separation is much less than the wavelength of light passing through it. Using a wider definition, the most common example of metamaterial would be an optical medium such as glass; here the objects would be the individual atoms or molecules making up the substance. The wavelength is the distance between repeating units of a wave pattern. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye, or in a more general sense, any electromagnetic radiation in the range from infrared to ultraviolet. ... The physics definition of a glass is a uniform amorphous solid material, usually produced when a suitably viscous molten material cools very rapidly, thereby not giving enough time for a regular crystal lattice to form. ... Properties For alternative meanings see atom (disambiguation). ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ...

However, it is possible to construct arrays of current-conducting elements (such as loops of wire) that have a magnetic response at microwave frequencies. When electromagnetic radiation passes the wire loops, the magnetic field could induce an electric current, thus producing magnetic response. In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ... The term induction has more than one meaning in the English language. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ...

Negative refractive index

Very nearly all materials encountered in optics, such as glass or water, have positive values for both permittivity ε and permeability μ. However, many metals (such as silver and gold) have negative ε at visible wavelengths. A material having either (but not both) ε or μ negative is opaque to electromagnetic radiation (see surface plasmon for more details). A falling water droplet Water (from the Anglo-Saxon and Low German wæter) is a colourless, tasteless, and odourless substance that is essential to all known forms of life and is the most universal solvent. ... This article is in need of attention. ... This article is in need of attention. ... General Name, Symbol, Number silver, Ag, 47 Chemical series Transition metals Group, Period, Block 11, 5, d Density, Hardness 10490 kg/m3, 2. ... General Name, Symbol, Number Gold, Au, 79 Chemical series transition metals Group, Period, Block 11 (IB), 6, d Density, Hardness 19300 kg/m3, 2. ... A substance or object that is opaque is neither transparent nor translucent. ... In physics, the plasmon is the particle resulting from the quantization of plasma oscillations, which are density waves of the charge carriers in a conducting medium such as a metal, semiconductor, or plasma. ...

Although the optical properties of a transparent material are fully specified by the parameters ε and μ, in practice the refractive index N is often used. N may be determined from . All known transparent materials possess a positive index because ε and μ are both positive. The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ...

However, some engineered metamaterials have ε < 0 and μ < 0; because the product εμ is positive, N is real. Under such circumstances, it is necessary to take the negative square root for N. Physicist Victor Veselago proved that such substances are transparent to light. Please refer to Real vs. ... See: transparency (optics) alpha compositing GIF#Transparency transparency (overhead projector) market transparency transparency (telecommunication) transparency (computing) For X11 pseudo-transparency, see pseudo-transparency. ...

Metamaterials with negative N have numerous startling properties:

• Snell's law (N₁sinθ₁ = N₂sinθ₂) still applies; but rays are refracted away from the normal on entering the material
• The Doppler shift is reversed (that is, a light source moving toward an observer appears to reduce its frequency)
• Cerenkov radiation points the other way
• group velocity is antiparallel to phase velocity (as opposed to parallel for normal materials)

One common metamaterial is the Swiss roll. Snells law is the simple formula used to calculate the refraction of light when travelling between two media of differing refractive index. ... The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ... Cherenkov effect at the [http://www. ... The group velocity of a wave is the velocity with which the overall shape of the waves amplitude (known as the envelope of the wave) propagates through space. ... Anti parallel- The two helices of Dna have sugar phospahte backbones that run in opposite directions. ... The phase velocity of a wave is the rate at which the phase of the wave propagates in space. ...

Such metamaterials follow a "left-hand rule".

The first Superlens (an optical lens employing negative refraction with vastly improved microscopic resolution) was created and demonstrated in 2005 by Xiang Zhang et al of UC Berkeley, as reported in the April 22 issue of the journal Science [1] (http://www.eurekalert.org/pub_releases/2005-04/uoc--nso041805.php)

External Links

• Experimental Verification of a Negative Index of Refraction (http://physics.ucsd.edu/lhmedia)