Brazilian researchers developed a lens a thousand times thinner than a human hair, which could be used to optimize the cameras of smartphones or other devices that depend on sensors.
“In the current technological context, its applications are almost limitless,” said Emiliano Rezende, professor at the San Carlos Faculty of Engineering (EESC-USP) of the University of Sao Paulo and author of the study “On metalenses with arbitrary field of view wide ”, published in ACS Photonics.
The lens consists of a single nanometric layer of silicon in arrays of nanoposts that interact with light. The structure is printed using photolithography, a technique used to make transistors.
This type of lens is known as a metalens. They were first developed ten years ago and achieve the highest resolution that is physically feasible, using an ultra-fine array of tiny waveguides called a metasurface that bends light as it passes through the lens.
According to Rezende Martins, metalenses have long faced the problem that the angle of view is extremely small (less than 1 °). “One way to solve the problem is to combine metalenses, forming complex structures”, Rezende explained.
“Our lens has an arbitrary field of view, which ideally can reach 180 ° without image distortion. We have tested its effectiveness for an angle of 110 °. With wider viewing angles, the light energy decreases due to the shadow effect, but this can be corrected by post-processing, ”he said.
Martins tested the metalenses with a 3D-printed camera and obtained high-resolution images with a wide field of view. “So far we have only managed to photograph in green, but in the coming months we will update the lens so that all colors are feasible,” he said.