Slashdot Mirror

← Back to Stories (view on slashdot.org)

A Step Toward an Invisibility Cloak

Posted by kdawson on from the can-you-see-me-now dept.

Technology Review has a writeup on the latest advance in the lab towards an invisibility cloak made of metamaterials, described this week in Science. We've been following this technology since the beginning. The breakthrough is software that lets researchers design materials that are both low-loss and wideband. "The cloak that the researchers built works with wavelengths of light ranging from about 1 to 18 gigahertz — a swath as broad as the visible spectrum. No one has yet made a cloaking device that works in the visible spectrum, and those metamaterials that have been fabricated tend to work only with narrow bands of light. But a cloak that made an object invisible to light of only one color would not be of much use. Similarly, a cloaking device can't afford to be lossy: if it lets just a little bit of light reflect off the object it's supposed to cloak, it's no longer effective. The cloak that Smith built is very low loss, successfully rerouting almost all the light that hits it."

14 of 197 comments (clear)

  1. Why not let a bit through? by artor3 · · Score: 5, Insightful

    Similarly, a cloaking device can't afford to be lossy: if it lets just a little bit of light reflect off the object it's supposed to cloak, it's no longer effective.

    Why would that be no longer effective? If the cloak reroutes 90% of the light, then you're left with 10% opacity, right? Sure, something that translucent would be very difficult to see, especially from a distance.

    1. Re:Why not let a bit through? by dotancohen · · Score: 5, Funny

      Why would that be no longer effective? If the cloak reroutes 90% of the light, then you're left with 10% opacity, right? Sure, something that translucent would be very difficult to see, especially from a distance.

      The Predator still got his ass shot up good with that hand-held vulcan gun, because the soldier saw the 10% of light that he couldn't cloak.

      --
      It is dangerous to be right when the government is wrong.
    2. Re:Why not let a bit through? by bloodninja · · Score: 5, Funny

      Yes, but if you look at it from a D&D point of view, you get a 90% miss chance, which is a game-breaking advantage.

      I put on my robe and wizard hat.

      --
      Lock the wife and the dog in the boot of the car.
      Return one hour later.
      Who's happy to see you?
  2. FUUUU by sakdoctor · · Score: 5, Informative

    Direct link please!
    http://www.technologyreview.com/computing/21971/?a=f

    Garbage javascript broke for me and the page didn't get past a white page.

    1. Re:FUUUU by Anonymous Coward · · Score: 5, Funny

      It's not broke... it's cloaked!

    2. Re:FUUUU by LearnToSpell · · Score: 5, Funny

      Yeah, but that link only rerouted 90% of the light. Here, try this one:

      --
      Haida Manga
  3. wavelength = length by Doviende · · Score: 5, Informative

    "works with wavelengths of light ranging from about 1 to 18 gigahertz"

    frequency is in hertz.
    wavelength is a length, so it will be in meters or feet or inches or volkswagen bugs.

    that is all. </pedantic>

    --
    "The value of a man resides in what he gives,
    and not in what he is capable of receiving."
    --Albert Einstein
    1. Re:wavelength = length by John+Courtland · · Score: 5, Insightful

      Yeah, but it doesn't matter too much since c is constant. It's easy to calculate wavelength for any given frequency.

      --
      Slashdot is proof that Sturgeon's Law applies to mankind.
    2. Re:wavelength = length by ZombieRoboNinja · · Score: 5, Funny

      Not for those of us who don't live in a vacuum, you insensitive clod!

  4. invisibility schmisibility by Anonymous Coward · · Score: 5, Funny

    Pics or it didn't happen.

  5. At last! by commodore64_love · · Score: 5, Funny

    Now I can see what happens inside the Girls' dorm!

    Giggity-giggity-goo.

    --
    "I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
  6. Re:One color invisibility certainly could be of us by Proteus · · Score: 5, Informative

    Bah, "ain't" is a perfectly valid contraction for "am not", and has been since at least 1706. (See http://www.etymonline.com/index.php?search=ain't&searchmode=none) Proscriptionists object to it largely because it's often used for "is not", or "are not", which was seen as somehow "perverting" the English language.

    In fact, though, "ain't" has been used that way since at least the 19th century.

    About the worst that you can say of "ain't" is that it's inappropriate for a formal register, but so are most contractions.

    Cheers,
    Your Friendly Neighborhood Pedant

    --
    We may not imagine how our lives could be more frustrating and complex—but Congress can. – Cullen Hightower
  7. 18 GHZ is NOT the width of the visible specturm by jschimpf · · Score: 5, Informative
    Visible light ~5000 - 7000 Angstroms (1X10-9 m)

    7000 -> f = lambda/c -> 4.28275E+14

    5000 -> f = lambda/c -> 5.99585E+14

    Difference -> 1.713E+14 Hz -> 1.713E5 GHZ

    About 171,000 GHZ not 17

  8. Re:Blindness by ORBAT · · Score: 5, Funny

    Seeing "cockpit" hyphenated like that led to some disturbing mental images.