Radiating Glass Fiber (IMAGE) Vienna University of Technology Caption An ultra-thin glass fiber emits light of different wavelengths. Theories going beyond Planck's law can describe this emission very accurately. Credit Vienna University of Technology 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.