Take a moment to imagine the possibilities of having your own cloak of invisibility. What would you do with it? Would you sneak into a room or house, spy on or scare a friend or relative, do something that is forbidden or take revenge on someone who wronged you? Alas, usually thoughts of fairy tales and fantasy stories such as Grimm’s fairy tales and the Harry Potter series come to mind when thinking of an invisibility cloak. It’s considered a thing of fiction. Well, science now comes forward to say that it can really exist.
Some researchers of the Karlsruhe Institute of Technology in Germany have developed an technique that makes the concept of an invisibility cloak possible. They have figured out how to cloak a tiny bump in a layer of gold, preventing its detection at nearly visible infrared frequencies. They have been able to use their cloaking technique in two and three dimensions. Their cloak is a structure of crystals with air spaces in between, similar to the structure of a woodpile and it bends light to hide the bump in the gold that lies beneath the cloak. In their trial run of the development, the actual bump was a mere 0.00004 inch high and 0.0005 inch across in size, so small only a magnifying lens would allow you to see it. But lead researcher Tolga Ergin reports that the cloak design can be modified to fit any size in principle, though larger sizes would require much more time to achieve.
Ergin goes on to explain that the cloaking technique helped researchers learn more about the field of transformation optics and they are now a step closer to creating 3-D structures in that field. Earlier discoveries about cloaking techniques were made by a research team led by David Schurig from Duke University. Schurig’s team discovered that microwaves can be used for cloaking in two dimensions. Similar to light and radar waves, microwaves tend to bounce off objects, allowing them to be seen by instruments, thus creating a shadow that can be detected. However, Ergin’s team used infrared waves, which are closer to the spectrum of light.
The cloaking technique works by deflecting radar, light and other waves around an object like fluid having to move around a solid barrier. The German Research Council, the state of Baden-Wuerttemberg, the European Commission and the German Ministry for Education and Research have supported the research of Ergin and his team. So, invisibility cloaks can exist after all.
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