Well, OK, not exactly. A beam of light could pass through air all day long (as long as you have a layer of air 26 billion kilometers long) and not deviate a whit. But if the density of that air ...

Physicists in Germany claim to have found the first naturally occurring material that has a negative, rather than a positive, refractive index. The material -- a metallic ferromagnet -- is very ...

A new class of optical thin-film materials enables the refractive index to be tuned to extremely low values. E Fred Schubert and colleagues believe that this capability could have important ...