Researchers have taken the next step on the road to constructing a cloak of invisibility or a powerful "superlens" capable of capturing fine details invisible to current lenses. A group from the University of California, Berkeley, this week is publishing the first demonstrations of materials capable of bending visible or near-visible light the "wrong" way in three dimensions.Cool, dude!
Both are examples of metamaterials—specially designed structures that cause light to do things it normally wouldn't—in this case, bending backward, an effect called negative refraction. Researchers have built metamaterials capable of negatively refracting microwaves, but despite some successes bending visible light in two dimensions, they've had a harder time making three-dimensional versions.
In a study to be published in Nature, the Berkeley group, led by Xiang Zhang, bent red light using a fishnet-shaped stack of 21 layers of silver and magnesium fluoride, each a few tens of nanometers thick (see diagram). (One nanometer is a billionth of a meter.) The group will also report in Science that it bent near-infrared light using a thinner sheet of aluminum oxide containing silver nanowires. The researchers believe that the second material ought to work on red light as well. - Scientific American