Circular polarized thermal radiation (IMAGE) Purdue University Caption Thermal Image of Wabash River (left), near Purdue University's campus. Most conventional objects show weak to zero circular polarization in the emitted heat signal. By using metasurfaces (right) made up of arrays of F-shaped nanostructures with various symmetries, researchers are able to generate circular polarized thermal radiation in a controlled and efficient manner. Credit Purdue University image/Xueji Wang Usage Restrictions No restrictions. License Public Domain 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.