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Cloaking devices

  1. Jan 15, 2009 #1
    I've read about new scientific discoveries in cloaking devices that bend microwaves and make it appear as though the waves go straight through the object. First of all, is what I read true? And secondly, would there be a method of modifying it to bend visible light, and if so, HOW?:confused:

    Any comments would aid in my understanding of this subject.

  2. jcsd
  3. Jan 15, 2009 #2


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    Yes it's true - it involves making complicated layers of structures that act like antennae on a scale smaller than the wavelength.
    It's not too difficult for microwaves (few cm wavelength) rather more tricky for visible light.

    There are a couple of problems using it for a 'cloaking device'
    It only works for a narrow range of wavelengths (ie color) so you might be able to do it for a single laser beam but not for white light.
    It works over the entire surface not for individual rays so you wouldn't see a picture of what was behind it - just a blurred blob (like frosted glass)

    How it actually works is (not surprisingly) complicated but they are called 'metamaterials' if you want to look up more.
  4. Jan 18, 2009 #3


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    A rather simple method has been developed for bending visible light waves around an object. Soldiers and field tested a suit made of hexagonal projection screens with pinhole cameras in between them. A fiber-optic two connects each pinhole camera to the screen on the opposite side soldiers body. An observer sees an image of what is on the other side of the soldier.

    However, this turned out to be an expensive and complicated arrangement with fairly low reliability and high maintenance. A sniper's "Gillie suit" accomplishes the same job (rendering the soldier virtually invisible) cheaply and with fewer malfunctions.
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