They Twisted Light on Gold – And What They Saw Blew Their Minds

Scientists in Germany have crafted “skyrmion bags” of light—complex vortex-like structures—on the surface of gold by cleverly manipulating how laser beams interact with nano-etched patterns.

This unusual feat not only adds a surprising twist to the physics of light but also hints at future technologies that could break the limits of current microscopes.

Skyrmion Light Bags: A New Breakthrough

“Our results add another chapter to the emerging field of skyrmion research,” proclaims Prof. Harald Giessen, head of the Fourth Physics Institute at the University of Stuttgart, whose team has achieved a remarkable breakthrough. The researchers have demonstrated the formation of “skyrmion bags” made of light on the surface of a metal.

Exploring the Vortex Structures of Light

Skyrmions are mathematical models of swirling, vortex-like structures that help scientists understand fundamental physical interactions. Initially a theoretical concept, skyrmions have since been observed in various systems, including magnetic materials and surfaces. Giessen’s group explored whether light interacting with a precisely structured gold surface could also form skyrmion-like patterns.

Their goal was to create skyrmion bags, a configuration where several smaller skyrmions are contained within a larger one. To achieve this, they etched intricate grooves shaped like two twisted hexagons onto a thin gold film. Each hexagon acted as a generator of a skyrmion-shaped light field.

Crafting Skyrmion Bags Through Surface Design

“We then observed a superposition of two skyrmion light fields, from which the skyrmion bags formed,” explains Julian Schwab, the study’s lead author and a doctoral researcher in Giessen’s group. Even more impressively, the team discovered that they could control how many skyrmions formed within each bag by adjusting how the two light fields were twisted relative to each other. This means they were able to precisely shape light fields into complex patterns that don’t naturally occur.

To verify their experimental results, the team worked with researchers from the University of Duisburg-Essen, and to model the theoretical behavior, they collaborated with scientists at the Technion in Haifa.

Unlocking Future Technologies Through Fundamental Physics

So far, this is still fundamental physics. However, these light-field skyrmions exhibit extraordinary properties, thereby sparking researchers’ imagination in terms of potential technical applications. Whether the gold surface used by Giessen’s team is suitable for this purpose remains to be seen. “If someone finds a suitable material, our concept could be applied in microscopy,” states Giessen. We could achieve resolutions with specialized microscopes that would otherwise be impossible because of the limits set by the wavelength of the light.

Reference: “Skyrmion bags of light in plasmonic moiré superlattices” by Julian Schwab, Alexander Neuhaus, Pascal Dreher, Shai Tsesses, Kobi Cohen, Florian Mangold, Anant Mantha, Bettina Frank, Guy Bartal, Frank-J. Meyer zu Heringdorf, Timothy J. Davis and Harald Giessen, 22 April 2025, Nature Physics.
DOI: 10.1038/s41567-025-02873-1

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