We are now one step closer to having a cloaking device. Scientists at Duke University have figured out a way to make objects invisible under special circumstances. Basically what they’ve done is to take advantage of a special class of material called metamaterials, which have quite unusual properties.
When light passes through matter, it bends. Different materials bend light different amounts; this is called the index of refraction. Generally the index of positive—this is why someone’s face looks distorted when seen through a glass of water, for example. But metamaterials are designed to channel electromagnetic radiation through specific channels. In other words, they are designed to bend electromagnetic radiation in ways that are not found in nature. These scientists have made a metamaterial that allows microwaves to bend around the copper ring that is hidden inside (see picture above).
It doesn’t work with light because the material is limited by scale: microwaves are centimeters in wavelength and therefore easier to manipulate than light, which is around 500 nanometers in wavelength (much smaller). Nanotechnology is not that advanced yet. But not only has a theory been proved, but there is also a working prototype of an invisibility cloak. It’s really only a matter of time until other technologies catch up and we can all have our own invisibility cloaks. Is this good or bad? The opportunities to abuse are endless, but this is the case with all new technology. Actually I can’t really think of a benign use of an invisibility cloak. Unless you are fighting evil. Then I would highly recommend use of an invisibility cloak.
Further reading from The New Scientist,