Harry Potter fans, do not despair! Invisibility cloaks may be a long shot, but last year physicists demonstrated technology that might someday hide you from radar. Now, two groups of researchers have taken steps toward performing the same trick with visible light.
Light rays passing from one transparent material to another generally refract, or change direction. That's why a pencil looks broken when partially submerged in water. Recently, physicists have begun to explore materials with a characteristic called negative refraction. If water had that property, the underwater half of the pencil would appear to stick out above the surface.
The first demonstration of negative refraction used materials that displayed the effect at o