Waveguide (IMAGE) Vienna University of Technology Caption Aluminium waveguide with a quadratic target in the middle (the cover plate is removed and not shown). The white teflon elements to the left and right of the target mimic a disordered medium. Credit TU Wien 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.