For a Low-Cost Invisibility Cloak, Physicists Look to Crystals

Forget about fancy metamaterials that can make microscopic objects invisible--researchers at two different universities have independently shown that larger objects can be rendered invisible using a mineral that's both naturally occurring and common: calcite. This latest step in physicists' ongoingquest to create an invisibility cloak come from an MIT lab, with a paper published in Physical Review Letters, and a University of Birmingham lab, whose paper just came out in Nature Communications. Both teams explained that they used calcite to make objects that are large enough to be seen with the naked eye invisible.