Material With Negative Refractive Index Created

holy_calamity writes "The race to build a material with a negative index of refraction for visible light has been won by researchers in Germany. The advance could lead to super-lenses able to see details finer then the wavelength of visible light, or the previously predicted invisibility cloak for visible light." From the article: "[The researcher] determined the refractive index of the material by measuring the 'phase velocity' of light as it passed through. His measurements show the structure has a negative refractive index of -0.6 for light with a wavelength of 780 nm [the far red end of the visible light spectrum]. This value drops to zero at 760 nm and 800 nm, and becomes positive at longer and shorter wavelengths."

Comments

Re:Negative or less than one?

[FooAtWFU]

So light goes backwards in this doodad?

Nope. Neither does light does not move faster than the speed of light, just phase groups. These crests and troughs of the light are features of the wave, but not any sort of signal or material in and of themselves. It's just an abstraction. Think of it this way: if you had two people a light-year apart, and they both raised their hands into the air at the same time to do The Wave, would you say that they sent a signal faster than the speed of light? If you had a one-light-year-long string of lights, and you rigged them all so they turned on at the exact same moment (presumably using some sort of countdown), would you say they've sent a signal faster than the speed of light? (Have you, in fact, sent a signal with infinite speed?) No, you haven't. You've gotten an abstraction to move faster than the speed of light, but that's not really very interesting for physics.