Wednesday, September 03, 2008

Invisibility Cloak Undone!

This has got to be an example of technology moving so fast that it literally trips over itself. Over the past several months we have been hearing more and more about tech being studied and developed that would allow a functional "invisibility cloak". Well it seems now that such a device may never happen. Why? Well it is not because a massive hole has been found in the concept, no, it's because a group of Chinese researchers have proposed a theoretical "anti-cloak" that would partially cancel the effect of the invisibility cloak, making the invisibility cloak technology partially infective. Their "anti-cloak" would be a material with optical properties perfectly matched to those of an invisibility cloak. Before you start cashing in your invisibility cloak stock, lets look at one of the major problems of a "truly" invisible material. Something that bends light around itself doesn't absorb any and doesn't reflect any. If you put a sheet of this material over yourself you would become blind. What the Chinese researchers have done is to solve this problem. Envisioning this problem, they developed in theory a way to cancel out small sections of the "cloak" so that you could see out.

Ingenious yes, but considering that we have only been able to bend certain wavelenghts of light so far and only in a lab, making "accessories" is something way on the fringe.

<- more in Science Daily ->


wolfkahn said...

I've thought about the blindness problem since first hearing about this idea. I imagine it would be relatively less difficult, and more effective" to create a cloak that only lets through either infrared or ultraviolet light in and equip the wearer with goggles than to use the Chinese method.

Paul said...

That was my thoughts initially, the argument was that if any radiation is absorbed, it's also reflected. If it is reflective, then it can be "seen" at some level. To be truly effective the "cloak" has to bend both passive and active wavelengths. I can remember the first time I had this train of thought. I can remember seeing one of the first Invisible Man movies and was convinced that was the coolest until it was put to me that you would be blind, so any advantage was moot. I came up with the bright idea of having just the retina visable. lol do I need to go further?!