| Mar 18, 2026 |
Researchers demonstrated a method to convert terahertz spin waves into charge signals via an optical intermediate step, advancing magnon-based spintronics.
(Nanowerk News) Physicists have demonstrated a method to convert terahertz spin waves into charge-compatible signals, bringing magnon-based data processing closer to integration with existing computer technology. The results, published in Nature Communications (“Coherence transfer from optically induced THz magnons to charges”), come from a German-Japanese collaboration led by Davide Bossini at the University of Konstanz.
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Key Findings
- Researchers achieved coherence transfer from optically driven terahertz magnons to charges through a measurable optical response.
- The method uses commercially available lasers and standard crystal samples, making it accessible for industrial applications.
- The team identified the specific conditions required for the spin-to-charge conversion and built a microscopic model that reproduces the experimental data without parameter fine-tuning.
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Spintronics uses the intrinsic angular momentum of electrons, known as spin, to store, process, and transmit data. The technology already underpins modern hard drives.
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But newer approaches go further, harnessing not individual spins but collective spin excitations called magnons, which can involve hundreds of trillions of spins oscillating together as waves. Because magnon generation and detection do not necessarily produce resistive heating, these spin waves could enable extremely energy-efficient data transfer at terahertz frequencies.
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The central obstacle has been coupling magnon-based signals to the charge-based CMOS technology that runs today’s computers. “If we develop a concept to perform computer calculations with magnons, it must be compatible with the technology we currently use,” said Bossini. “To reach this goal, you have to convert the spin wave into an electrical charge signal.” This spin-to-charge conversion is considered one of the major unresolved challenges in the field.
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From spin wave to electrical signal through light
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The new study demonstrates a two-step pathway for that conversion. In the first step, the magnetic signal carried by terahertz spin waves is transformed into an optical signal. “Under certain conditions, the magnetic signal of spin waves can be converted into an optical signal,” Bossini explained. “We show that magnons can also influence the optical properties of a material. It remains a magnetic signal, but it has measurable optical properties.” In the second step, this optical signal can be coupled to electrons, producing the electrical charge signal that conventional electronics can process.
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Standard materials, transferable results
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A deliberate feature of the approach is its reliance on ordinary materials and equipment. “You don’t need highly specialized signals for our process,” said Bossini. “But you need to fulfil certain conditions, and we have now identified these conditions.” The team used laser pulses at wavelengths between 400 and 900 nanometres, spanning the visible and near-infrared spectrum. While the exact wavelengths depend on the material, the underlying principle transfers readily to other systems.
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Bossini’s group intentionally avoids exotic materials in their experiments. Ensuring that results can be reproduced by other laboratories and scaled to industrial use is a priority. The experiments used commercially available lasers and standard crystal samples, and were performed at temperatures of 10 Kelvin (minus 263 degrees Celsius).
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Beyond the experimental demonstration, the researchers developed a microscopic theoretical model that reproduces their measurements without any adjustment of free parameters. The paper, authored by Moritz Cimander, Volker Wiechert, Julian Bär, Takuya Satoh, Jörg Bünemann, Götz S. Uhrig, and Davide Bossini, represents a collaboration between the University of Konstanz, TU Dortmund University, and the Institute of Science Tokyo. Bossini heads an Emmy Noether research group at the Department of Physics in Konstanz, where his team studies light-matter interactions on ultrafast timescales, with a focus on charge and spin dynamics in magnetically ordered materials.
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By establishing a concrete mechanism for transferring coherence from terahertz magnons to charges, and by identifying the precise conditions under which this transfer occurs, the work provides a practical foundation for connecting magnon-based spintronics with the CMOS electronics that dominate current computing infrastructure. The use of standard laboratory equipment and widely available materials positions the method for adoption by other research groups and, potentially, for industrial implementation.
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