Negative refraction index

  • #1

Main Question or Discussion Point

I am sure this topic has been discussed a million times so how can once more hurt?

I am only just being introduced to physics at school and a question came to mind when I was thinking about a game called "Crysis" in which the main character can become invisible. 'Cloaking' or 'invisibillity' have been widely discussed and thought about topics for a long time, and I am wondering what a negative refraction index would achieve if it was somehow applied to a material?
 
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Answers and Replies

  • #2
Born2bwire
Science Advisor
Gold Member
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Yes, a left-handed (double negative, metamaterial, insert buzz-word here) can be used to create an invisibility cloak. They have already worked out and published the theory on how to do this and have demonstrated a example in experiment for a 2D version in RF.

Short answer, cool but pointless in most ways. For a true invisibility cloak, you would have to be completely incased and you would not be able to see out because all of the incident light is bent around and reemitted. If any of the light penetrated the cloak, then it would be detectable in a change in phase, polarization, and/or intensity. Current metamaterials can only work at a single frequency or very very narrow bandwidth. The ability to create a metamaterial even at visible light frequencies has yet to be achieved and we have yet been able to create a metamaterial that can work across a range of frequencies. Finally, the current theory requires a constant geometry for the "cloak." So it isn't really an invisibility cloak, more like an invisibility giant hamster ball.

....

Actually, and invisibility hamster ball would be pretty cool...

I think the theory papers were published with some general details in Nature maybe one or two years ago or so. Took them longer to come up with the idea than I thought they would.
 

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