Researchers Develop An Invisibility Cloak That Hides Objects from Touch
Move over, witchcraft, because science has created invisibility cloaks for nearly every sense. Over the past several years, scientists have built devices that render objects invisible to sight, sound, and heat. Now, researchers from The Karlsruhe Institute of Technology (KIT) have created a mechanical "invisibility cloak" that can hide objects from the sense of touch.
[Credit: T. Buckmann]
This device is constructed from a specific kind of material, called a metamaterial, in order to protect objects on the lower side from detection through the sense of touch. The metamaterial is composed of a crystalline polymer that has an intricate structure on a sub-micrometer level. The structure consists of needle-shaped cones that meet at the tip. "We build the structure around the object to be hidden. In this structure, strength depends on the location in a defined way," explains Tiemo Bückmann, KIT, the first author of the article. "The precision of the components combined with the size of the complete arrangement was one of the big obstacles to the development of the mechanical invisibility cloak."
Once the structure is produced, a hard cylinder is inserted at the bottom, in which an object can be hidden. While many layers of foam or other material may prevent the cylinder from being detected to some extent, the metamaterial directs the forces of touch in such a way that the cylinder (and the object within it) are completely hidden. "It is like in Hans-Christian Andersen's fairy tale about the princess and the pea. The princess feels the pea in spite of the mattresses. When using our new material, however, one mattress would be sufficient for the princess to sleep well," Bückmann explains.
This technology is particularly groundbreaking since it represents a newfound ability to manipulate a substance's chemical properties to very exact specifications. As a result, we may be able to manufacture materials with properties that cannot be found in nature, such as being hard to pressure from solids, but soft to liquid. This could have significant implications for consumer products; for example, we might be able to make a very thin and light mattress that is still soft and comfortable.