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Nano-Scale Optical Co-Axial Cables Announced

Posted by ScuttleMonkey on from the hairy-logic dept.

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."

6 of 157 comments (clear)

  1. huh? by macadamia_harold · · Score: 5, Funny

    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.

    methinks the speed of light is whatever speed the light travels at.

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    1. Re:huh? by Anonymous Coward · · Score: 5, Insightful

      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.

    2. Re:huh? by Incongruity · · Score: 5, Insightful

      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.

  2. Thosands of times faster than electronics? by JesseL · · Score: 5, Informative
    From TFA:
    "It's not quite the speed of light, but it's probably 90 percent the speed of light. That's still thousands of times faster than electronics," Naughton said in an interview.


    It was my understanding that electric fields propagate through copper at about 1/3 C.
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  3. Re:WTF? by kebes · · Score: 5, Informative
    Well put. The original scientific article in question is this one:

    Rybczynski, J.; Kempa, K.; Herczynski, A.; Wang, Y.; Naughton, M. J.; Ren, Z. F.; Huang, Z. P.; Cai, D.; Giersig, M. "Subwavelength waveguide for visible light" Applied Physics Letters 2007, 90, (2), 021104. (doi: 10.1063/1.2430400).

    The paper is here, although only subscribers can read the fulltext. The abstract says this:

    The authors demonstrate transmission of visible light through metallic coaxial nanostructures many wavelengths in length, with coaxial electrode spacing much less than a wavelength. Since the light frequency is well below the plasma resonance in the metal of the electrodes, the propagating mode reduces to the well-known transverse electromagnetic mode of a coaxial waveguide. They have thus achieved a faithful analog of the conventional coaxial cable for visible light. ©2007 American Institute of Physics
    These are extremely small structures and this leads to an interaction between the light (which is an electromagnetic wave of course) that is essentially identical to when radiofrequency EM radiation propagates down a normal (macroscopic) coax cable. Specifically, in the introduction they say:

    In this work, we show experimentally that a nanoscopic analog of the conventional coaxial cable, with properly chosen metals for the electrodes and proper electrode dimensions, indeed retains approximately all of the above properties of its conventional macroscale cousin.
    Then they go through the details. Their device uses a multiwall carbon-nanotube (MWCNT) as the center conductor (it is a 'metallic' CNT). The MWCNT is embedded in aluminum oxide, which acts as the optically transparent 'dielectric'. The outer wrapping electrode is made of chromium.

    The mere creation of these nano-sized devices is quite an accomplishment. The fact that they've demonstrated successful transmission of light through these sub-wavelength sized devices is even more impressive. I can imagine a wide range of applications in nano-scale imaging (imagine a massive array of NSOMs), lithography, or even optical computing.
  4. Re:WTF? by MustardMan · · Score: 5, Informative

    Yes, I DO have faith in the peer review process. It's far from perfect, but it's not as bad as you make it out to be. The thing you need to know is, a lot of physicists, and scientists in general (myself included) can be really anally retentive bastards. I one got blasted for fifteen minutes over my use of the phrase "high reynolds number" when the colleague in question believed "moderate" was the appropriate adjective and "high" was misleading. These are the types of errors that get physicists steaming, and with good reason - physics is perhaps the most rigorous of the sciences, and you have to be damn careful about how you word things. People will complain, loudly, about very minor issues. Many scientists strive for absolute perfection, and fixate on the negatives in an attempt to make the process better. There's nothing wrong with this, but it's useful to keep in mind when you form opinions about the peer review process based on your friends' complaints.

    When people bitch about physics journals, in my experience it's been mainly for two common reasons:
    1.) Drawing large, over-arching conclusions without enough evidence to support it. This is in no way saying the bulk of the work is invalid, just that the authors got a little greedy when writing the conclusions.
    2.) Disagreement with the underlying assumptions that make up the paper. This one is trickier, but again it doesn't immediately invalidate the work, just questions how relevant the results are.

    In either case, the peer review process, by people well-versed in the field, is a whole HELL of a lot more trustworthy than the slashdot peanut-gallery. The OP was full of crap, and others have gone into great detail to explain why he/she is full of crap. 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.