Researchers develop a millimeter-size flat lens for VR and AR platforms
A metalens fabricated on 2-inch glass wafer (left) and a scanning fiber mounted via a piezo tube (proper). The fiber tip locates inside the focal size of the metalens. Light travels alongside the fiber and emits out from the scanning fiber tip, the place a show sample kinds. Credit: Zhaoyi Li/Harvard University

Despite all of the advances in shopper know-how over the previous many years, one element has remained frustratingly stagnant: the optical lens. Unlike digital units, which have shrunk and extra environment friendly over time, the design and underlying physics of right this moment’s optical lenses have not modified a lot in about 3,000 years.


This problem has triggered a bottleneck within the improvement of next-generation optical methods similar to wearable shows for digital actuality, which require compact, light-weight, and cost-effective elements.

At the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), a workforce of researchers led by Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, has been growing the subsequent era of lenses that promise to open that bottleneck by changing cumbersome curved lenses with a easy, flat floor that makes use of nanostructures to focus mild.

In 2018, the Capasso’s workforce developed achromatic, aberration-free metalenses that work throughout the whole seen spectrum of sunshine. But these lenses had been solely tens of microns in diameter, too small for sensible use in VR and augmented actuality methods.

Now, the researchers have developed a two-millimeter achromatic metalenses that may focus RGB (crimson, blue, inexperienced) colours with out aberrations and developed a miniaturized show for digital and augmented actuality functions.

A metalens for virtual and augmented reality
The increase actuality imaging end result utilizing the full-color near-eye fiber scanning show, which exhibits an RGB-color digital picture floating in a real-world scene. Credit: Zhaoyi Li/Harvard University

The analysis is revealed in Science Advances.

“This state-of-the-art lens opens a path to a new kind of virtual reality platform and overcomes the bottleneck that has slowed the progress of new optical device,” mentioned Capasso, the senior creator of the paper.

“Using new physics and a new design principle, we have developed a flat lens to replace the bulky lenses of today’s optical devices,” mentioned Zhaoyi Li, a postdoctoral fellow at SEAS and first creator of the paper. “This is the largest RGB-achromatic metalens to date and is a proof of concept that these lenses can be scaled up to centimeter size, mass produced, and integrated in commercial platforms.”

Like earlier metalenses, this lens makes use of arrays of titanium dioxide nanofins to equally focus wavelengths of sunshine and get rid of chromatic aberration. By engineering the form and sample of those nanoarrays, the researchers might management the focal size of crimson, inexperienced and blue coloration of sunshine. To incorporate the lens into a VR system, the workforce developed a near-eye show utilizing a technique referred to as fiber scanning.

Researchers develop a millimeter-size flat lens for VR and AR platforms
Credit: Harvard John A. Paulson School of Engineering and Applied Sciences

The show, impressed by fiber-scanning-based endoscopic bioimaging strategies, makes use of an optical fiber via a piezoelectric tube. When a voltage is utilized onto the tube, the fiber tip scans left and proper and up and right down to show patterns, forming a miniaturized show. The show has excessive decision, excessive brightness, excessive dynamic vary, and extensive coloration gamut.

In a VR or AR platform, the metalens would sit instantly in entrance of the attention, and the show would sit inside the focal airplane of the metalens. The patterns scanned by the show are centered onto the retina, the place the digital picture kinds, with the assistance of the metalens. To the human eye, the picture seems as a part of the panorama within the AR mode, a long way from our precise eyes.

“We have demonstrated how meta-optics platforms can help resolve the bottleneck of current VR technologies and potentially be used in our daily life,” mentioned Li.

Next, the workforce goals to scale up the lens even additional, making it suitable with present large-scale fabrication strategies for mass manufacturing at a low value.


Single metalens focuses all colours of the rainbow in a single level; opens new potentialities in digital, augmented actuality


More data:
Zhaoyi Li et al. Meta-optics achieves RGB-achromatic focusing for digital actuality, Science Advances (2021). DOI: 10.1126/sciadv.abe4458

Citation:
Researchers develop a millimeter-size flat lens for VR and AR platforms (2021, January 27)
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