The lens is quite unlike the curved disks of glass familiar from cameras and binoculars. Instead, it is made of a thin layer of transparent quartz coated in millions of tiny pillars, each just tens of nanometres across and hundreds high.

Singly, each pillar interacts strongly with light. Their combined effect is to slice up a light beam and remould it as the rays pass through the array

Source: Flat lens promises possible revolution in optics – BBC News

“The quality of our images is actually better than with a state-of-the-art objective lens. I think it is no exaggeration to say that this is potentially revolutionary.”