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Updated: Sep 30, 2026

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
Published on: November 21, 2019
Magneto-optics in the ultrafast regime: thermalization of spin populations in ferromagnetic films
Luca Guidoni1, Eric Beaurepaire, Jean-Yves Bigot
1Institut de Physique et Chimie des Matériaux de Strasbourg, Unité Mixte CNRS-ULP-ECPM, 23 rue du Loess, 67037 Strasbourg Cedex, France. Luca. Guidoni@ipcms.u-strasbg.fr
Abstract:
We have characterized by pump-probe polarimetry the time-dependent dielectric tensor in a CoPt3 ferromagnetic film excited by 20 fs laser pulses. It is shown that, after the thermalization time of the electrons (approximately 50 fs), the dynamics of the real and the imaginary parts of the Voigt vector are identical. In addition, their relative variation is 10 times larger than that of the diagonal elements of the tensor, which allows one to infer that the spins dominate the magneto-optical response. During the thermalization process, the temporal behavior of the tensor elements opens new questions concerning the dynamics of the spins associated to a nonthermal electronic population in a ferromagnet.
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