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Asked by sanban to Chris, Dave, David, Fiona, Jack on 21 Jun 2013.
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Chris Mansell answered on 21 Jun 2013:
Metamaterials are materials that have been very carefully designed so that they affect the propagation of waves (e.g. light waves or sound waves) in interesting ways. They do this by have pattern features in their structure that are smaller than the wavelength of the waves with which they are designed to interact.
I am not sure I have fully got to grips with the device you are envisioning. However, if you are interested in making things invisible, there has been quite a lot of work done in this area:
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David Freeborn answered on 22 Jun 2013:
Metamaterials are materials that are able to get completely new properties by combining other materials in a particular way.
For example, by arranging gold and copper in certain shapes and patterns we can make a material that combines their properties in a particular way, and also has some entirely new properties. We can design metamaterials that can guide light rays in a particular way.
Metamaterials might be able to make objects “invisible” by guiding the light rays around the object. If we can make it work, it will be far, far more effective than any of the currently “invisibility cloaking” devices, based on optical sensors and computers, like this:
British scientists are putting research into making an invisible tank.
We might also be able to make metamaterial “cloaking devices” for magnetic fields and for heat as well.
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Dave Farmer answered on 23 Jun 2013:
Hi sanban,
When an electromagnetic wave travels through a ‘normal’ material, it is the electric part of the wave that interacts strongly with the structure. In metamaterials, the structure is designed to interact with the magnetic part of the wave as well. This can give rise to exciting new properties such as materials with a negative refractive index! This allows structures to be made that can control the path of electromagnetic waves (such as light) in new ways.
I’m not quite sure what it is you’re asking with the second part of your question. Metamaterials are able to bend electromagnetic waves around objects, making them invisible as you suggest. It would depend on how your cube was made, but if each face was the same then I don’t think it would appear any different from one way or the other.
Hope that answers your question, if not, let me know and I’ll have another go!
Dave
Comments
sanban commented on :
What I mean from the second part is this: some light will be incident on it from suppose left side..it absorbs it and sort of gives it off from the right side…some other light which was incident on it from right will be absorbed and the same light (same in wave length polarization and all things) will be emitted from the left. Now the body has to emit and absorb things both from the same side…How will I differentiate which photon to absorb and which to emit? Also it is easy to visualise this considering light as particles but what if I think it as wave?
Chris commented on :
This is an interesting idea. James Bond had an invisible car in Die Another Day. It had cameras and light emitters on every outer surface. Everything a camera saw on the left, a light emitting device would project from the right. I think this is fairly similar to your idea. Does that help?
Dave commented on :
Hi sanban, I think you’re thinking about it slightly the wrong way. In a metamaterial, the light isn’t adsorbed and then re-emitted. They can be used to manipulate light is previously impossible ways though, hence their potential for invisibility cloaks, they can bend the light around an area (the cube in your case).