The Reality of Invisibility Cloaks.

"As a boy I believed I could make myself invisible. I'm not sure that I ever could, but I certainly had the ability to pass unnoticed."

Terence Stamp

Hey all you muggles out their who don't possess an invisibility cloak may be wishing for one, but what you might not know is that the technology out there needed for this is already being developed and isn't far out of reach.
Possibly the biggest advancement into the field has got to be metamaterials. Metamaterials are artificial structures smaller than the wavelength of light. In order for an invisibility cloak to work it needs to bend light around an object with minimal distortion.
All materials have a value called a refractive index; with natural materials having a positive refractive index, for example:
-Air - 1.000293
-Water - 1.3330
-Ice - 1.31
-Diamond - 2.419
These refractive index dictates how light interacts with each material. By altering a material at the microscopic level it can change the way light interacts with it - this can even be used to change it's refractive index from a positive value to a negative.
In 2006 a metamaterial was created able to deflect microwaves round a plane, of course humans don't see through the microwave spectrum although with technological advancements enough to change this technology we may just be able to bend visible light soon.
In our life-times.
In 2007 a metamaterial was created able to bend light round an object, advancements on this have created a concept able to bend sound waves round an object as well. With this type of technology the possibilities are endless.

Use the concept of water bending round
a rock in a stream/river to help visualise
light bending round an object.

Invisibility cloaks are only the start - invisible ammo for guns, invisible tanks, even invisible buildings, entire structures!
This technology also has the possibility to bring the world to it's knees. With every great advancement in science there comes a price - think about the impact of the nuclear/atomic bomb.

This technnology however is far from perfect. These metamaterials are minute - and a suit made from them would not only be extremely costly but would be enormously heavy as well. The technology of cloaking devices such as these needs so much work before the world becomes full of invisible men.

Thanks for reading, Chris.