New Discovery Challenges Scientific Understanding of Light-Matter Interaction

Nov. 27—Researchers at the Hebrew University of Jerusalem have overturned a 180-year-old scientific assumption, proving that the magnetic component of light plays a critical role in how light interacts with matter, according to their results, published Nov. 19 in Scientific Reports. The study established that the magnetic influence is quantifiable and significant, accounting for approximately 17% of the rotation in visible light and rising to 70% in the infrared spectrum—factors previously considered negligible in optical physics.

Previously, the scientific community attributed the rotation of light’s polarization with a magnetic field exclusively to the interaction between the light’s electric field and the electric charges within the material. The new study clearly shows that the magnetic field of light makes a direct and measurable contribution to this effect. “In simple terms, it’s an interaction between light and magnetism,” said Dr. Amir Capua, one of the study’s authors. “The static magnetic field ‘twists’ the light, and the light, in turn, reveals the magnetic properties of the material. What we’ve found is that the magnetic part of light has a first-order effect, it’s surprisingly active in this process.”

Benjamin Assouline, the other author of the study said that the results show that light “talks” to matter through its magnetic field. Capua added: “In other words light doesn’t just illuminate matter, it magnetically influences it.”

“The discovery opens the door to new possibilities in optics and magnetism,” conclude the researchers, “including applications in spintronics, optical data storage, and light-based magnetic control. It may even contribute to future spin-based quantum computing technologies.”