Nano-Scale Optical Co-Axial Cables Announced

toybuilder writes "Reuters reports that scientists have published their work on nano-scale optical coax in the most recent issue of Applied Physics Letters. The coax cable is only about 300nm wide, and is able to transmit optical signals using a carbon center conductor, transmitting light at about 90% the speed of light."

Re:huh?

[Anonymous Coward]

Light always travels at 100% of the speed of light. However, in this cable, light travels at about 90% of the speed of light in a vacuum.

Re:huh?

[Incongruity]

Hardly -- the statement is a little stupid because it doesn't mention the constant c nor "the speed of light in a vacuum", it simply says "the speed of light" -- most people will recognize the error, but it's still an error.

Re:WTF?

[Bill, Shooter of Bul]

I was merely pointing out that the knee-jerk slashdot "post early, post often" karma whoring competitions lead to a whole lot of dumbass assertions without any firm understanding of the actual facts of the discussion.

But thats what slashdot is. Its a discussion forum. It wasn't a stupid question, as you can see it was asked in other places in this subject.Its about the exchange of ideas and is what makes slashdot a *good* place. Its like instant wikipedia that has people pooling their collective areas of expertise together. Just reading a summary, I can usually guess the topics that are going to be raised and discussed because people feel free to express their knee jerk reactions. It makes the discussion richer in the end. It helps me get a sence of what other people are thinking and why they think that way. I don't want people to self sensor themselves, (thats what the mods are for (no, seriously .. stop laughing, the mod system works ... usually).

Re:Coax is silly for optical

[StikyPad]

That's only because 99% of coax in common use is single conductor electrical shielded cable, which is to coax as sheep are to mammals. Electrical shielded cable is just a type of coax cable. Also the function of the shielding is to eliminate EMI, not to provide any sort of return path. That it is typically connected at both ends is incidental -- it's just the simplest method of grounding the insulation.

Re:Coax is silly for optical

[Goldsmith]

They use coaxial wires so that their waveguide can be long and skinny.

It's thinner than the wavelength of the light, which is not possible with fiberoptics. There are other ways of making subwavelength waveguides, but they don't work over long distances. In the co-ax, light is transmitted basically as if it were in free space, and doesn't attenuate very much. In most nanostructures used for optics, light is transmitted as a plasmon (a rather quickly attenuating surface bound state).

There's a bonus third effect: By replacing the optically clear insulator between the conductors with something more exotic, you can do light mixing and switching. These guys don't actually do that, but mention the possibility in their conclusion.

Re:Coax is silly for optical

[smellsofbikes]

You're closer to convincing me than anyone else.
So tell me why the wavelength of light matters: it's longitudinal, not transverse, so what limits it? Does light have a diameter at all? I guess there's an amplitude, some function of the electronic/magnetic components. I know they're 90 degrees to one another. Are the two the same amplitude? Does it matter that it runs into things? I guess an electric field shouldn't be able to cross a conductor, but is that absolute, or is there some penetration into the conductive surface?