Metasurfaces for Ultrathin Camera Lenses

With those flexible metasurfaces camera lenses could be in future thousands of times thinner and significantly less resource-intensive to manufacture. (Source: D. Andren, Chalmers U.)

In the future, camera lenses could be thousands of times thinner and signi­ficantly less resource-intensive to manu­facture. Researchers from Chalmers University of Technology, Sweden, now present a new tech­nology for making meta­surfaces, which consist of a multitude of inter­acting nano­particles that together can control light. They could have great use in the optical tech­nology of tomorrow. Meta­surfaces can be used for optical components in portable electronics, sensors, cameras or space satellites. The Chalmers researchers’ new tech­nology for making such planar surfaces is based on a plastic that is already used today to create other micro­structures.

“We put a thin layer of this plastic on a glass plate and, using electron-beam litho­graphy, we can draw detailed patterns in the plastic film, which after develop­ment will form the meta­surface. The resulting device can focus light just like a normal camera lens, but it is thousands of times thinner – and can be flexible too,” says Daniel Andrén, a PhD student at the Department of Physics at Chalmers.

Over the past ten years, there has been a revolution in optics. The phones in our pockets have cameras com­parable to a DSLR – technological masterpieces with millions of pixels of reso­lution. They process light with small advanced computer chips and software, and the image is recreated with the help of small coloured LEDs. These techno­logies have developed extremely rapidly in recent years, due mainly to smaller and more effec­tive circuit components. However, camera lenses themselves have not changed as much. The majority of today’s lenses are based on the same physical principles, and include the same basic limitations, as the first proto­types invented in the sixteenth century. In the past decade, however, researchers have begun to work with metasurfaces that could replace today’s lenses.

Currently, certain issues stand in the way of large-scale manu­facturing of meta­surfaces. Advanced equipment is required to manufacture them, and the process is also very time-consuming. But using the Chalmers researchers’ new method, the production rate can be increased several times compared to current state-of-the-art techniques. The new techno­logy uses harmless chemicals, as well as machines that are already common in nano-manu­facturing labora­tories today, meaning that more researchers could now begin to study metasurfaces.

“Our method could be a step towards large-scale production of meta­surfaces. That is the goal we are already working towards today. Meta­surfaces can help us create different effects and offer various techno­logical possi­bilities. The best is yet to come,” says Ruggero Verre from the Department of Physics at Chalmers. (Source: Chalmers U.)

Reference: D. Andrén et al.: Large-Scale Metasurfaces Made by an Exposed Resist, ACS Phot. 7, 885 (2020); DOI: acsphotonics.9b01809

Link: Nano and Biophysics, Dept. of Physics, Chalmers University of Technology, Göteborg, Sweden

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