Scientists at the University of Texas in Austin have successfully “cloaked” a three-dimensional object in free space for the first time. Unfortunately they were only able to do so for waves in the microwave region of the electromagnetic spectrum, meaning we can’t actually “view” the invisibility with the naked eye.
Previous attempts at cloaking have been limited to two-dimensional objects or simply theoretical in nature. In the latest experiment, researchers were able to hide a three-dimensional cylindrical tube roughly 7.1-inches in length and 1-inch in diameter from microwaves in any direction in a natural environment.
To accomplish this marvel of science, the tube was covered by a shell coated with a plasmonic metamaterial that scatters light and electromagnetic waves. The shell is able to precisely cancel the light scattered by an object. By effectively cancelling out any light that would normally scatter off an object, it appears transparent.
There are a few drawbacks, however. At present, the cloak can only hide dielectric objects, not metal. Furthermore as stated earlier, the effect only works for polarized microwave light and thus isn’t visible to the naked eye. As Martin Wegener suggests, one would have to put on polarizing goggles to appreciate the cloaking.
Andrea Alu, the University of Texas professor who worked on the project and co-author of a paper published in the Institute of Physics and German Physical Society's New Journal of Physics, believes that there are some real-world applications where such a cloak could be useful. Biomedical and optical near-field measurements could be greatly improved and in the future, aircraft could be coated with the material to appear invisible to all forms of radar in any direction.