Macro Image (IMAGE) University of Bonn Caption The picture shows the two glass fibers (top center). Their ends are reflectively coated such that they form a so-called resonator. The rubidium atom is inserted between them. After excitation, it then radiates the photons primarily in the direction of the mirrors (and thus of the glass fibers). The mirrors have a diameter of only 0.1 mm. Credit © Jose Gallego / University of Bonn 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.