negative refractive index/metamaterials

[papernuke]

How can a metamaterial make the refractive index negative? Although i know they are just theoretical. also, what would happen when you are hiding behind/wearing something that is metamaterial. do the light rays just bend around the metamaterial?

[Keiji]

They would reflect off, wouldn't they?

http://en.wikipedia.org/wiki/Metamaterial

[pat]

Yes, they would reflect off... but not obeying the whole angle-of-incidence=angle-of-reflection rule. You could probably get a somewhat similar effect with a mesh of tiny triangular prisms or corner-mirrors (though not right-angle corner mirrors).

And, this article: http://physicsworld.com/cws/article/news/24975 shows how you could use a metamaterial with negative refractive index to bend light around the center. But, it has to be a very particular shape and size for a given refractive index.

[papernuke]

But how do the metamaterials bend the rays so they go almost-exactly in the direction they came in? shouldnt it just bend it weirdly so you cant directly see the figure, but you can see a mass of contorted shimmers in the air..?