It sounds like something from a sci-fi novel reshaping matter with nothing but light. Yet, a team of physicists at the University of Konstanz has done just that. By using laser pulses to excite magnon pairs, tiny ripples of magnetic energy within crystals they’ve discovered a way to change a material’s magnetic “fingerprint” without heat, rare materials, or extreme conditions. As lead researcher Davide Bossini put it, “The result was a huge surprise for us. No theory has ever predicted it.”
At the heart of this discovery lies haematite, a simple, naturally occurring iron oxide crystal that once guided ancient sailors through magnetic compasses. Today, it may be steering humanity into the next generation of data and quantum technology.
The Konstanz team found that by firing ultrafast laser pulses at haematite, they could coherently excite pairs of magnons the highest-frequency magnetic resonances in the material. Magnons are waves created by the collective motion of electron spins, and in this case, their behavior can be altered without adding heat. “The cause is light, not temperature,” Bossini emphasized.
This non-thermal control means that light alone can reshape the material’s magnetic properties, effectively rewriting its “magnetic DNA.” As Bossini described, “It changes the nature of the material, the ‘magnetic DNA of the material,’ so to speak, its ‘fingerprint’. It has practically become a different material with new properties for the time being.”
The implications stretch far beyond the lab. Magnons can transmit and store information at terahertz frequencies, far faster than traditional electronics. And since the process doesn’t generate significant heat, it sidesteps one of the biggest challenges in high-speed data systems: overheating.
Even more astonishing is the possibility of achieving quantum effects at room temperature. Normally, such delicate phenomena require cooling near absolute zero. But with haematite and this laser-driven method, researchers may soon be able to create light-induced Bose–Einstein condensates of magnons a state of matter that behaves according to quantum mechanics without any cryogenic equipment.
As the study’s authors noted, the technique requires no exotic or rare materials. Haematite is abundant, inexpensive, and stable making it an ideal candidate for scalable quantum and spintronic applications.
This work, conducted under the Collaborative Research Centre SFB 1432 “Fluctuations and Nonlinearities in Classical and Quantum Matter beyond Equilibrium”, marks a profound step forward in understanding how light can directly manipulate the building blocks of matter.
