Frequency Doubling (IMAGE) ETH Zurich Caption Red light is transformed into blue light by frequency doubling inside tiny spheres made of nanocrystals. Credit ETH Zurich / Jolanda Mueller 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.