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Magnetic Field of Light Shown to Drive Faraday Rotation, Challenging 180-Year Assumption

A peer-reviewed model using spin dynamics quantifies a sizable, wavelength-dependent magnetic contribution that now awaits experimental confirmation.

Overview

  • Hebrew University researchers led by Dr. Amir Capua and Benjamin Assouline report the first theoretical proof that light’s magnetic field directly contributes to the Faraday effect.
  • Calculations based on the Landau–Lifshitz–Gilbert equation show the oscillating optical magnetic field can exert a torque on spins similar to a static magnetic field.
  • Applying the model to Terbium Gallium Garnet estimates about 17% of the rotation in the visible range and up to 70% in the infrared.
  • The work is published in Scientific Reports and reframes the effect long attributed solely to interactions with light’s electric field.
  • Igor Rozhansky of the University of Manchester deems the calculations convincing and points to plausible experimental tests and spintronic applications.