By carefully arranging nanostructures on a flat surface, researchers at Linköping University have significantly enhanced the performance of optical metasurfaces made from conductive plastics. This advancement marks a key step toward controllable flat optics, laying the groundwork for potential applications such as video holograms, invisibility materials, sensors, and biomedical imaging.
Dongqing Lin and Magnus Jonsson examing a sample by the scanning electron microscope. Image Credit: Thor Balkhed
Traditionally, controlling light has relied on curved glass lenses, either concave or convex, that refract light in specific ways. These lenses are everywhere, from sophisticated tools like space telescopes and radar systems to everyday items such as cameras and eyeglasses. However, their size and shape limit how compact and flexible optical systems can be.
Flat lenses, or metalenses, offer an alternative. These are examples of optical metasurfaces—an emerging area of optics research with immense promise.
Unlike traditional lenses, metalenses can be extremely compact and integrated into new types of devices. But there’s a catch: the technology has, until now, faced performance and tunability challenges.
Metasurfaces work in a way that nanostructures are placed in patterns on a flat surface and become receivers for light. Each receiver, or antenna, captures the light in a certain way and together these nanostructures can allow the light to be controlled as you desire.
Magnus Jonsson, Professor, Applied Physics, Linköping University
Tuning is Key
Many current metasurfaces are made from materials like gold or titanium dioxide, which are static—once manufactured, their optical function can’t be changed. Researchers and industry alike have long sought metasurfaces that could be actively controlled, whether to switch them on and off or to dynamically shift the focal point of a lens.
In 2019, Jonsson’s team at the Laboratory of Organic Electronics demonstrated that conductive plastics, or conducting polymers, could meet this challenge.
These materials behave optically like metals and can be toggled on or off thanks to their ability to oxidize and reduce. This made it possible to build switchable nanoantennas from polymer-based metasurfaces. However, their performance lagged behind metasurfaces made from traditional materials.
Tenfold Improvement in Performance
Now, the same team has achieved a tenfold improvement in performance. By fine-tuning the spacing between the nanoantennas, the researchers enabled them to interact more effectively through a phenomenon known as collective lattice resonance, which amplifies how they interact with light.
We show that metasurfaces made of conducting polymers seem to be able to provide sufficiently high performance to be relevant for practical applications.
Dongqing Lin, Study Principal Author and Research Postdoc, Linköping University
So far, the team has developed switchable polymer antennas that operate in the infrared spectrum. The next challenge is adapting the technology for visible light—an essential step toward broader practical use.
The research was supported by the European Research Council, the Knut and Alice Wallenberg Foundation, the Swedish Research Council, and Sweden’s Government Strategic Research Area in Materials Science on Advanced Functional Materials (AFM) at Linköping University.
Journal Reference:
Lin, D., et al. (2025) Switchable narrow nonlocal conducting polymer plasmonics. Nature Communications. doi.org/10.1038/s41467-025-59764-5