Friday, October 19, 2012

How metamaterials interact with electromagnetic waves


This article was found on http://www.helium.com

It was written by Effie Moore Salem

Created on: February 17, 2011 Last Updated: February 18, 2011

Metamaterials and electromagnetic fields belong together, but before any conclusive statements can be made concerning how they react, individual introductions must first be made:

  1. Metamaterials are specially designed materials purposely created to interact with electromagnetic waves. According to Materials Science and Engineering, "Metamaterials are composite systems whose properties are dominated not by the individual atoms, but by the properties of larger, artificially produced structures or "meta-atoms".
  2. The way light reacts to these substances is different than the usual reaction. This is so because materials deliberately have been reworked or infiltrated with atoms in such a way that when the light falls on these materials it has counter reactions to those that would normally occur.
  3. Electromagnetic waves are oscillating electrical and magnetic fields such as radio waves, microwaves, X-rays, and just plain old light. The spectrums of electromagnetism are all different in ranges and this makes up their differences in their reactions to substances they encounter, accidentally or on planned.
  4. How do these interact? The light waves from the electromagnetic field enter the metamaterial and force the atoms to move. This produces energy. The force of that energy depends on how the metamaterials have been constructed, and for what purpose. All materials are made from atoms but what makes the atoms comprising the light waves, or magnetic fields invisible is their extremely small size. Only the results of their interactions can be seen, heard, or felt. It is these interactions that make their presence known, and it by these that they are measured, and made useful.

Examples of their usefulness are all around: Opticians make use of them every day in creating eyewear , in examining eyes and in other similar types of devices. This interaction makes possible microscopes, eye glasses, and telescopes. These are nothing more than plastic or glass that make us of light rays by changing the way the light waves interact with the material.

Light waves can be directed from one place to another by forces which pull light through carefully constructed metamaterials. The lens of a pair of glasses, microscopes, telescopes are example of a metamaterial. One advance in electromagnetic technology leads to another. Scientist using the known ways in which atoms and molecules react with one type of material, will use that to create even more uses for this type of energy. The type of materials used make all the difference.

By creating different kinds of material with which electromagnetism can react, different effects can be realized. And all this are possible by pushing the limits of the electromagnetic field. And these of course must be known. If the objects to be met by electrified light are smaller and spaced differently than the wavelength of light, the light will not be able to make up for the difference. Is this good or bad?

It depends on the project at hand, and innovators are making use of this disadvantage of wavelengths to create metamaterials that will do more than what has been done with naturally occurring materials. Even so, these new materials are also made of atoms, but the difference is in the technique. No longer must chemistry synthesis with its set rules guide the outcomes. Simply by creating new materials geometrically different, newer interactions are possible.

The idea for making use of, or even of creating such materials, dates back to 1968 when Victor Veselago proposed "left-handed" materials could be made useful. His idea was all but forgotten until 2000. The MRI, as one example was made possible because of this property between the interaction - or negative reaction - between metamaterials and electromagnetism. Other non-medical uses are making heavier insulating materials lighter, shortening or otherwise improving antennas, and so on.

Thus, the interactions between metamaterials - materials met by electromagnetic fields - and their reactions and their non-reactions are ongoing studies at this time.

Source:

  1. Source 1 HERE
  2. Source 2 HERE.
  3. Source 3 HERE.
  4. Source 4 HERE.
  5. Source 5 HERE.

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