Manipulating matter with light is much more promising than scientists thought.

Nanotechnology

Technological Innovation Website Editorial Team - September 22, 2025

Science and art: Illustration of the physics phenomenon known as "Floquet states," which has now been observed in graphene for the first time. The illustration shows the three-dimensional electronic structure of graphene—known as Dirac cones —and its replicas created by light. [Image: Lina Segerer (www.linasegerer.de)]

Floquet Effect

Graphene has been somewhat hidden because, although promising in a variety of areas - flexible screens, sensors, powerful batteries, solar cells, etc. - it is very difficult to manufacture graphene on an industrial scale .

But, even though there were plenty of reasons to invest in this, now there's one more: It's possible to manipulate the properties of two-dimensional materials using only light, which takes their potential for technological and scientific applications to a whole new level.

Researchers from the universities of Göttingen (Germany) and Fribourg (Switzerland) have directly observed Floquet effects for the first time, using graphene. These effects allow nothing less than the control of matter using light .

The demonstration also resolves a long-standing debate among physicists, who believed that Floquet engineering - a method in which a material's properties are altered with high precision using pulses of light - would not work on metallic and semi-metallic materials such as graphene.

Thus, this proof puts the entire family of two-dimensional (2D) materials, or van der Waals materials , in the sights of scientists - today we already know that there is an entire universe of one-dimensional materials , recently enriched with 2D metals .

Floquet engineering demonstrated in graphene. [Image: Marco Merboldt et al. - 10.1038/s41567-025-02889-7]

Light-controlled materials

The researchers used femtosecond momentum microscopy to experimentally investigate Floquet states in graphene. In this technique, samples are first excited with quick flashes of light and then examined with a delayed light pulse to track dynamic processes in the material.

"Our measurements clearly prove that 'Floquet effects' occur in the photoemission spectrum of graphene," said Professor Marco Merboldt. "This makes it clear that Floquet engineering really works in these systems—and the potential of this discovery is enormous."

Indeed, this shows that Floquet engineering works on a much wider range of materials than previously thought. In practical terms, this means that the long-dreamed-of goal of designing new materials with specific properties, and doing so using laser pulses in an extremely short time, is getting closer, the researchers say.

Configuring materials in this way for specific applications could form the basis for the electronics, computers, and sensor technology of the future.

"Our results open up new ways to control electronic states in quantum materials with light. This could lead to technologies in which electrons are manipulated in a targeted and controlled manner," said team member Professor Stefan Mahias. "What is particularly exciting is that this also allows us to investigate topological properties. These are special and very stable properties, with great potential for the development of reliable quantum computers or new sensors in the future," added his colleague Marcel Reutzel.

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