Cloak of Invisibility Emerges from the Labs

To make a Harry Potter-style invisibility cloak requires the use of materials that have what's known as a negative refractive index over all optical wavelengths, from red to violet. 

You don't see yourself.

However, the artificially-structured optical materials from which cloaks are made thus far have been restricted to a very narrow range of optical wavelengths, limiting their ability to cloak over a range of colors. 

That obstacle to progress looks to be at an end, as a group of optical engineers at Stanford has succeeded in designing a broadband metamaterial that exhibits a negative refractive index over nearly the entire rainbow...

The broad bandwidth of the new Stanford metamaterial suggests that this new class of materials will one day allow the fabrication of invisibility cloaks that are truly invisible, at least to the human eye. Beyond this, the extraordinary freedom to control light with metamaterials is likely to lead to hordes of applications never previously imagined. (more) (original paper) (lab-shirt) (How to hide a bug from an IR viewer.)

Imagine the impact on eavesdropping and spying.