The Cloak of Invisibility: Challenges and Applications

A nyone who’s read the Harry Potter books by J.K. Rowling understands the concept of an invisibility cloak. Furthermore, humans have dreamt of what invisibility might mean since the beginning of civilization, and this dream persists in today’s literature and culture. However, although more improbable methods of invisibility will remain unrealized, an invisibility cloak could be feasible in the future through technology. In this article, we attempt to show this via technical “pencil and paper” arguments and a conceptual implementation. Generally speaking, we propose a fabric of small computing devices that can receive and retransmit light emissions in a directional way as well as interact with each other in a wireless amorphous network.1 While someone or something is inside the cloak, the cloak’s devices would cause external observers to perceive the light configurations they would see if the wearer wasn’t there. Sensors on the side of the cloak not facing the observers could receive such configurations and, via distributed coordination, communicate them to emitters on the observer’s side for retransmission. Building a solid wall exhibiting such properties for a nonmoving observer might be difficult. Even more challenging problems arise when preserving such properties