It would have many uses including military applications, radar tracking
Imagine a tennis player hitting a ball against a wall. The ball would bounce right back to the player no matter what angle he or she directed the shot. A universal mirror has the same effect, except with light waves. Unlike an ordinary mirror, which only reflects objects at 90 degrees, a universal mirror reflects objects back at any angle. In other words, a person positioned in front of a large, optical universal mirror would see his or her own reflection perfectly no matter where the person stands.
“(A universal mirror) makes things become very visible,” said Ulf Leonhardt, a professor at the University of St. Andrews and co-author of a paper in the current issue of Nature Materials. “It’s the exact opposite of an invisibility cloak.”
Unlike a universal mirror, an invisibility cloak guides light waves around an object in order to conceal it. Although universal mirrors and invisibility cloaks might perform opposite functions, they each employ the same technology: metamaterials.
While the properties of normal materials are predominantly determined by their chemical composition, metamaterials are artificial materials that derive their properties from their physical structures. (more)