Unlike traditional lenses, the metalens is flat and compact and could be made small enough to fit inside increasingly miniaturized devices. The development, say the researchers, could lead to game-changing advances in solar energy, virtual reality technology, medical imaging and other applications reliant upon optics.
"We have overcome what was regarded as a fundamental roadblock," said study principal investigator Boubacar Kanté, associate professor of electrical engineering and computer sciences at UC Berkeley and faculty scientist at Lawrence Berkeley National Laboratory. "This is, simply, the thinnest, most efficient, broadest band flat lens in the world."
The new technology is described in a paper titled “Octave bandwidth photonic fishnet-achromatic-metalens” in the journal Nature Communications. The team demonstrated the ability of its fishnet-achromatic-metalens to capture 70% of incoming light in frequencies ranging from 640 nanometers (reddish-orange light) to 1,200 nanometers (infrared light). Light entering the fishnet metalens within that broad octave band of wavelengths would be focused at a single point on the other side of the lens.
"We are very excited by these results because many applications required the simultaneous processing of multiple wavelengths in a broad spectrum," said Kanté. "This is the case for solar energy applications where we need to focus all colors of light for efficient solar cells or solar concentrators." A good next step, Kanté said, would be to develop processes that could enable larger scale production.