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Originally Posted by xelasnave
Very interesting proposition G Day It is hard to imagine that any material could have a negative index ......anything showing the materials that are able to produce negative refraction?
I assume this would mean in the practical sense that one would use a concave lens as an objective in place of the convex objective lens in a refractor
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Alex
It seems to be almost more the material structure then the material itself. They are boring millions of tiny, tiny holes thru a substance to create this impressive effect - nano tubes a thousandth the size of the diameter of a human hair.
Lens shape could be flat! Its the tubes that do the work. Imagine either a static piece of glass that looked like window pane but was almost a perfect - far better than difraction limited lens. Secondly I read that more exotic materials and composite structures may have dynamically alterably refractive index. Imagine a flat 3 metre cylinder of glass that could act as a perfect parabolic mirror, alterable in a split second between F1 up to F30 , depending on how you run a current through it - wouldn't that be something!