Serveur des thèses de l'Université de Strasbourg

Coherent ultra-fast magneto-optics

VONESCH, Hélène (2011) Coherent ultra-fast magneto-optics. Thèses de doctorat, Université de Strasbourg.

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Abstract

In this work we have studied the ultra-fast interaction of photons and spins in ferromagnetic materials. At first, we have detailed the origin of magneto-optical effects and the different physical processes intervening in ultra-fast magnetization dynamics, especially in the coherent dynamics. We have used a simple model based on eight levels of the Hydrogen atom to explore two aspects of ultra-fast magneto-optical experiments: the importance of the spin-orbit interaction with the laser field appearing in the relativistic Foldy-Wouthuysen development, and the relation between the magneto-optical signal and the ultra-fast magnetization dynamics at short pump-probe delays. We have modeled two types of four-wave mixing experiments: a pump-probe configuration and a three beam setting, which enabled us to distinguish between the coherences’ and the populations’ magneto-optical response. We have shown that in our simple model, the spin-orbit interaction appearing in the Foldy-Wouthuysen development acts on the magnetization dynamics in the case of a strong Zeeman interaction. We have illustrated experimentally the two different magneto-optical dynamics for the populations and coherences in a three beam four-wave mixing experiment performed on a thin garnet film. This work announces progresses in the understanding of the coherent interaction between spins and photons in ferromagnetic materials as well as the possibility of controlling magnetization coherently on a femtosecond timescale.

Item Type:Thesis
Discipline de la thèse / mémoire / rapport :Physique. Physique de la matière condensée
Uncontrolled Keywords:dynamique d’aimantation ultra‐rapide ; optique ultra‐rapide ; magnéto‐optique ; expérience pompe‐sonde ; interaction cohérente ; populations ; Foldy‐Wouthuysen ; ferromagnétisme
Subjects:CL Classification > DDC Dewey Decimal Classification > 500 Sciences de la nature et mathématiques > 530 Physique > 539 Physique moderne > 539.1 Structure de la matière
Classification Thèses Unistra > Sciences, technologies > Sciences de la nature et mathématiques > 530 Physique > 539 Physique moderne > 539.1 Structure de la matière

UNERA Classification UNERA > ACT Domaine d'activité UNERA > ACT-3 Chimie, matériaux, plasturgie
UNERA Classification UNERA > DISC Discipline UNERA > DISC-20 Physique, chimie, matériaux
CL Classification > DDC Dewey Decimal Classification > 600 Technologie (sciences appliquées) > 620 Sciences de l'ingénieur > 621 Génie mécanique. Physique appliquée > 621.3 Electrotechnique, éclairage, électronique, télécommunications > 621.34 Technologie du magnétisme
Classification Thèses Unistra > Sciences, technologies > Sciences appliquées > 620 Sciences de l'ingénieur > 621 Génie mécanique. Physique appliquée > 621.3 Electrotechnique, éclairage, électronique, télécommunications > 621.34 Technologie du magnétisme
ID Code:2440
Deposited On:04 June 2012

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