Invisibility Cloak

Through the Rabbit Hole..."Imagine wrapping Harry Potter's invisibility cloak around a tube," says Greenleaf. "If the material is designed according to our specifications, you could pass an object into one end, watch it disappear as it traveled the length of the tunnel, and then see it reappear out the other end."

Researcher now think invisibility can occur at all frequencies, not just at one (microwave) as previously thought. With this in mind, possible applications include increasing the accuracy of MRI (Magnetic Resonance Imaging) in surgical situations as..."the intense magnetic fields generated by the MRI scanner affect the surgeon's tools, and the tools can distort the MRI images. Greenleaf says, however, that passing the tools through an EM wormhole could effectively hide them from the fields, allowing only their tips to be "visible" at work. "

Recently, scientists have begun building Metamaterials, composites that generate a negative index of refraction whereby the refraction or bending of light "bounces" through the transparent material in similar fashion to how light bounces off a mirror. except that the angle of reflection does NOT equal the angle of incidence (as per a mirror) in the metamaterial construct. The diagram below shows how negative indexing works.

When looking at this from an invisibility perspective, interesting things happen..."a reverse mirror thus have what's called a negative index of refraction. A lens made from such a material wouldn't have to be curved. (It's the curvature of an ordinary lens that enables it to focus incoming light.) Metamaterials could also be used to route electromagnetic waves around an object, rendering it invisible."

The problem with using this material as an invisibility cloak was cost and difficulty of production, something that hindered research into this outrageous tech until now. "Rather than requiring intricate structures, such as the split rings used in the microwave cloaking device, the materials can be made simply by stacking up extremely thin layers of semiconductor material. What's more, that stacking can be done by the same tools now used to make semiconductor materials for lasers used in telecommunications."

Now, researchers from the group of Harald Giessen at the University of Stuttgart have succeeded in manufacturing a stacked split-ring metamaterial for the optical wavelength range.

"Toto, I don't think we are in Kansas anymore" - Wizard of Oz
Invisibility: Predator Tech (BRT - TUESDAY, JUNE 12, 2007)

Addendum:The Invisibility Cloak is even a bigger deal than I thought. Click here to see why.