Researchers at the US National Institute of Standards and Technology have made a set of tiny metalens.
The nanopillars captured the light of the photographedscenes and separated it depending on the direction of the electric field: light from the left and right circular polarizations was deflected at different angles. This was achieved thanks to the arrangement of nanopillars. They were arranged so that some of the incoming light would pass through the long side of the rectangle and some through the short side. As the light travels longer distances, the deflection angle increases.
The developers explain that the light thatrefracted at different angles, hits different camera focuses. Thus, depending on whether the light has passed through the longer or shorter part of the rectangular nanopillars, the metalens creates images of nearby or distant objects. The resolution depth of the camera ranges from a few cm to 1.7 km.
According to the researchers, the biggest problemarose with objects that are located at an average distance. Scientists used a neural network to teach the system to recognize and correct defects (blurring or color aberration) in objects that were in the middle between the near and far focus of the metalens.
The developed metalens increase the luminosity withoutdamage to image resolution. In addition, because the system automatically corrects for aberrations, it is highly error-tolerant, allowing researchers to use simple and easy-to-make designs for miniature lenses.
Amit Agrawal, study co-author at the National Institute of Standards and Technology
Image: S. Kelley/NIST
The developers note that the idea of creating suchthey borrowed lenses from the device of the eyes of trilobites (Dalmanitina socialis). These animals inhabited the oceans about 500 million years ago. As the researchers note, these sea creatures had bifocal eyes, each of which is mounted on a stalk and consists of two lenses that refract light at different angles. Such an arrangement of the eye allowed trilobites to simultaneously see prey swimming nearby and distant enemies approaching from a distance of more than a kilometer.
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