03 June 2016
Vol 352, Issue 6290

About The Cover

Cover image expansion

COVER Nanoscale titanium dioxide fins in an ultrathin planar lens (a metalens) focus visible light (entering from the bottom and propagating upward) with high efficiency down to a subwavelength spot (yellow area). Due to their ultracompact geometry and high-resolution imaging capabilities, metalenses have potential to replace conventional lenses in a wide range of applications, such as cameras, wearable displays, and microscopes. See page 1190.
Image: Second Bay Studios