The great unappreciated weakness of invisibility cloaks is that they only make things invisible to human eyes. Or x-ray imagers. Or ultraviolet sensors, infrared image analyzers, echo-location audio signal receivers or, in one case, a poking finger.

Invisibility cloaks, which are very successful in movies and so close to being successful in labs that the million or so physicist working on them can taste it, have a crucial weakness: They make things invisible to the perception of the audience their creators had in mind.

Invisibility cloaks are supposed to hide things by bending light around them in a that would not allow any to be reflected back at a potential viewer, which would allow the “invisible” thing to be seen.

To read this article in full or to leave a comment, please click here

…