Harvard researchers have made advancements in development of a flat lens known as a metalens – for the first time, it can work with a continuous range of colors rather than one at a time. Research has been ongoing at the University's School of Engineering and Applied Sciences, showing last summer that it was possible to create a lens 100,000x thinner than glass that could focus light in the visible spectrum.
This metalens uses an array of titanium dioxide nanopillars to direct light, eliminating the need for additional curved glass layers to correct for chromatic aberration caused by traditional lenses. In fact, engineers were even able to design a metalens with reverse chromatic dispersion, showing that such technologies can really break away from the constraints imposed by traditional optical methods.
Varying the shape, size and height of the nanopillars used by the metalens allows it to focus wavelengths from 490nm to 550nm, or from blue to green. This is a promising step toward potentially using flat lens technology in anything from smartphone cameras to VR headsets.
. dpreview.com2017-2-9 13:00