Saturday, June 02, 2018 by David Williams
It seems like camera sensors, such as the ones used in digicams and cell phone cameras, improve each year. But the final image quality doesn’t just rest on the image sensors themselves. Another big contributor to the image quality from these types of cameras is none other than the camera lens.
Camera lenses are largely modeled from the natural lenses found in the eyes of humans – as well as other animal species, in some cases. Now a team of researchers has taken the standard lens concept and applied methods that effectively combined the worlds of semiconductor manufacturing and lens-making. As a result, they’ve created something they call an adaptive metalens, and it’s described as “essentially a flat, electronically controlled artificial eye.”
The researchers said that their adaptive metalens can simultaneously control three different major contributors to blurry images, namely astigmatism, focus, and image shift. The details of this new lens as well as the methods that they used to created it have been shared in a paper that was recently published in the journal Science Advances.
According to Alan She, a graduated student at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), they’ve managed to take concepts from several different fields of eye research and applied it to lens-making techniques. “This research combines breakthroughs in artificial muscle technology with metalens technology to create a tunable metalens that can change its focus in real time, just like the human eye,” he explained. “We go [sic] one step further to build the capability of dynamically correcting for aberrations such as astigmatism and image shift, which the human eye cannot naturally do.”
The adaptive metalens described and created by the researchers is grounded in artificial eye research, and only serves the function of the lens in a simple image capture equation. It’s rather simple in its construction, but it has enormous potential in the fields of imaging. As Frederico Capasso, a professor of Applied Physics and senior author of the paper states, their adaptive metalens can raise the bar for cameraphone image quality and more.
“This demonstrates the feasibility of embedded optical zoom and auto-focus for a wide range of applications including cell phone cameras, eyeglasses and virtual and augmented reality hardware,” Capasso said. “It also shows the possibility of future optical microscopes, which operate fully electronically and can correct many aberrations simultaneously.”
Even the most advanced modern cameras can benefit from this technology. In a normal lens that offers optical zoom, there are usually many moving parts involved. And that’s true not just for the lens itself, but also inside the camera itself, where the actual image gets taken and eventually printed or sent out. This is where the idea of a highly compact optical zoom comes in. The less moving parts, the better, for there are fewer parts that can potentially break during operation. The fact that it can offer superior image quality at the same time is just a wonderful bonus.
The researchers noted that artificial eyes can also suffer from the same issues as modern digital cameras. Alan She himself remarked that all optical systems which contain multiple components, from cameras to microscopes and even telescopes, could have slight misalignments or worse – unavoidable mechanical stress on all the different mechanical parts. That’s where the advantages of their invention come in.
“Because the adaptive metalens is flat, you can correct […] abberations and integrated different optical capabilities onto a single plane of control,” said She. If the researchers can scale up their invention, they could have a winner on their hands.