The new invisibility cloak changes that: The gold bricks reflect the light in such a way that the light's
phase and frequency are both preserved. (Phase is an angle measurement that tells you how far
along a light wave you are; two waves 180 degrees out of phase cancel out.) The ultrathin cloak
creates an effect that makes it seem like the light were hitting a perfect mirror and the cloak and
object weren't even there. Even the edges are invisible with the new device, the researchers said.