Waveguide and Graphene Sheet (IMAGE) Vienna University of Technology Caption The light signal arrives through a waveguide (left), in the 2 micrometer wide graphene sheet, electrical current is generated. Credit TU Vienna Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.