Washington State University (WSU) physicists have found a way to write an electrical circuit into a crystal, opening up the possibility of transparent, three-dimensional electronics that, like an Etch A Sketch, can be erased and reconfigured.
Ordinarily, a crystal does not conduct electricity. But when the researchers heated up crystal strontium titanate under the specific conditions, the crystal was altered so that light made it conductive. The circuit could be erased by heating it with an optical pen.