Engineers design nanostructured diamond metalens for compact quantum technologies
(PHYSorg.com Nanotechnology)

At the chemical level, diamonds are no more than carbon atoms aligned in a precise, three-dimensional (3-D) crystal lattice. However, even a seemingly flawless diamond contains defects: spots in that lattice where a carbon atom is missing or has been replaced by something else. Some of these defects are highly desirable; they trap individual electrons that can absorb or emit light, causing the various colors found in diamond gemstones and, more importantly, creating a platform for diverse quantum technologies for advanced computing, secure communication and precision sensing.