Metasurface and algorithms focus images for micro-camera

Researchers at Princeton University and the University of Washington have overcome fuzziness, distortion and limited fields of view associated with previous micro-cameras to produce an ultra-compact camera the size of a grain of salt. The new system is claimed to produce full-colour images on par with a conventional compound camera lens. The researchers have reported their findings in Nature Communications.

Enabled by a joint design of the camera’s hardware and computational processing, the system could enable minimally invasive endoscopy with medical robots to diagnose and treat diseases, and improve imaging for other robots with size and weight constraints. Arrays of thousands of such cameras could be used for full-scene sensing, turning surfaces into cameras.

The new optical system uses a half a millimetre wide metasurface covered with 1.6 million cylindrical posts. Each post has a unique geometry, and functions like an optical antenna. Varying the design of each post is necessary to correctly shape the entire optical wavefront. Using machine learning-based algorithms, the posts’ interactions with light combine to produce the highest-quality images and widest field of view for a full-colour metasurface camera developed to date.