My Jaffa Cake wrote:
The only issue with current cloaking technology is even if they managed to make it work is thermal signatures.
Not only are you visible on thermal scopes but current cloaking actually spikes heat, making you appear radiantly on any thermal device
If i understand the current metamaterial theory and optics transformation, the current (2006) proof of concept and test made to a cloaking device only works at microwave wavelenghts, for a small size copper cylinder. Metamaterials are created to join the best characteristics of any given natural material who, for themselves, possess no such characteristic or only a small amount of it, with the ability to fine tune to any given specs or requirements.
As for cloaking devices, a metamaterial could be fine-tuned to any given spec, in theory. The idea behind cloaking is to bend light around the object. Other concepts involve, for example, special cloths for active camo. These cloths or fibers are hardwired to a image capture device. So, the cloth would project in front what's behind, giving the illusion that there is nothing in between.
Given our current tech level, metamaterials for cloaking are still in their infancy but the idea behind them is to bend light around the object, with specific fine tuning for an array of situations. Since no light is reflected or absorbed, but rather diverted, the issue is to create such a metamaterial as to cover a wide array of wavelenghts.
Thermal radiation, that is, electromagnetic radiation emanating from any given body due to it's temperature is the basis behind thermal imaging. We can see that as the red and hot log on a fireplace, or a piece of charcoal. When the temperature lowers, the red get's dimmer until it disappears. But the object might still be hot, although it only emits thermal radiation below red, that is to say, on the infrared spectrum, invisible to us humans.
That poses a problem towards an effective cloaking device. Thermal radiation is dependent on emitted radiation by the body. This radiation crosses a wide range of frequencies. So, any material made to disguise that outgoing radiation would have to bend it around or anything else beyond my domain. What i know is that it couldn't absorb the radiation or else it would behave close to a black body, the best absorber of light and the best emitter of thermal radiation. That would render the cloak useless again in thermal imaging.
I'm having some trouble finding theoretical papers regarding cloaking thermal radiation but i'm sure there is a bunch of guys thinking that **** up....