New “Metalens” Shifts Focus Without Tilting or Moving

Polished glass has been at the center of imaging systems for centuries. Their precise curvature enables lenses to focus light and produce sharp images, whether the object in view is a single cell, the page of a book, or a far-off galaxy. Changing focus to see clearly at all these scales typically requires physically moving a lens, by tilting, sliding, or otherwise shifting the lens. This is usually done with the help of mechanical parts that add to the bulk of microscopes and telescopes.