cmirrors (IMAGE) University of Wisconsin-Madison Caption The heart of this study is a fiber microcavity. Here, one can see a small concave depression in the surface of an optical fiber. The researchers used a microcavity with two concave mirrors, but this image of a single concave microcavity makes it easier to see the fiber mirror setup. Credit Photo by Carlos Saavedra / UW–Madison Usage Restrictions None License Original 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.