Phys.org: Engineers design nanostructured diamond metalens for compact quantum technologies

The practical challenge of collecting information from a single atom deep inside a crystal is a daunting one, however. Penn Engineers addressed this problem in a recent study in which they devised a way to pattern the surface of a diamond that makes it easier to collect light from the defects inside. Called a metalens, this surface structure contains nanoscale features that bend and focus the light emitted by the defects, despite being effectively flat. Source: Phys.org