Berlin 2024 – scientific programme

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MA: Fachverband Magnetismus

MA 3: Ultrafast Magnetization Effects I

MA 3.5: Talk

Monday, March 18, 2024, 10:45–11:00, H 2013

Influencing ultrafast demagnetization with the OAM of light — •Paul Herrgen, Eva Prinz, Benjamin Stadtmüller, and Martin Aeschlimann — Department of Physics and Research Center OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany

As bosons, photons always have a spin angular momentum, which is associated with left- or right-handed circular polarization. This angular momentum is limited to values of ± 1ℏ. Additionally, the photons can also have an orbital angular momentum (OAM). With an angular momentum of lℏ with l ∈ Z it is possible to increase the total angular momentum of the photons drastically.

In contrast to the spin angular momentum, we found a significant influence of the orbital angular momentum of light on the ultrafast magnetization dynamics. Interestingly, the photonic OAM changes the magnetization only after the interaction of the light pulse with the material [1]. Furthermore, we find a clear relationship between the influence of photonic OAM and the angle between the wave vector of the OAM beam and the magnetization. These empirical results provide the basis for a microscopic model of the OAM-driven magnetization dynamics.

[1]: Prinz et al., arXiv:2206.07502

Keywords: MOKE; ultrafast; thin film; OAM of light