Magnetic and light vortices
Magnetic helicoidal dichroism is observed when an extreme ultraviolet vortex beam, carrying Orbital Angular Momentum (OAM), interacts with a magnetic vortex. Classical electromagnetic simulations predict this dichroism based on the interference of light OAM modes, populated after the interaction with the magnetic topology.
Fanciulli et al., Physical Review Letters, Vol. 128 - 7, p. 077401 (2022).
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Magnetic vortices can form in mesoscopic dots that are much larger than their thickness, leading to a planar magnetization with curling direction either clockwise (m = +1) or anticlockwise (m = -1), which we can associate with a toroidal moment. To observe them, we use extreme ultraviolet light pulses, generated by the FERMI FEL, carring OAM (l = 0, ±1) after the interaction with spiraling zone plates. Photon energy was 52.8 eV, matching the Fe 3p → 3d core resonance. Magnetic helicoidal dichroism is observing by measuring the resonant scattering of the OAM carrying beam from an iron nichel permalloy dot in micromagnetic vortex configuration. |
We compare the experimental results to theoretical predictions and we interpret them in terms of the interference between the different modes of the reflected light. Retrieve articleObservation of Magnetic Helicoidal Dichroism with Extreme Ultraviolet Light Vortices.
Fanciulli M., Pancaldi M., Pedersoli E., Vimal M., Bresteau D., Luttmann M., De Angelis D., Ribič P.R., Rösner B., David C., Spezzani C., Manfredda M., Sousa R., Prejbeanu I.L., Vila L., Dieny B., De Ninno G., Capotondi F., Sacchi M., Ruchon T. |
