The Science of Invisibility Cloaks

Who hasn't imagined how much easier life might be with Harry Potter's invisibility cloak or the cloaking device that hid the Romulan ship from Star Trek's USS Enterprise? Well, you don't need to go to Hogwarts School of Witchcraft and Wizardry in order to learn how to make an invisibility cloak, at least in theory.

Two U.K. studies in the 26 May 2006 issue of the journal Science now offer a hypothetical explanation for how a cloaking device could work. The trick is to guide the waves of light (or other types of electromagnetic radiation) around an object so that they proceed as if they had not been scattered by the object at all.

And what type of material is up to such a task? Authors John Pendry and colleagues and Ulf Leonhardt propose using metamaterials, which are engineered composite materials whose electromagnetic properties can be tuned by design, (i.e. by manipulating their nanostructure) instead of their chemistry. The properties of these materials could be "tuned" in such a way that when electromagnetic waves encountered the cloaking device they would produce neither a reflection nor a shadow.

Kathy Wren

26 May 2006