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Updated: Jun 21, 2026

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
Femtosecond coherent control of spins in (Ga,Mn)As ferromagnetic semiconductors using light
M D Kapetanakis1, I E Perakis, K J Wickey
1Department of Physics, University of Crete, Heraklion, Crete 71003, Greece and Institute of Electronic Structure & Laser, Foundation for Research and Technology-Hellas, Heraklion, Crete 71110, Greece.
Abstract:
Using density matrix equations of motion, we predict a femtosecond collective spin tilt triggered by nonlinear, near-ultraviolet (approximately 3 eV), coherent photoexcitation of (Ga,Mn)As ferromagnetic semiconductors with linearly polarized light. This dynamics results from carrier coherences and nonthermal populations excited in the {111} equivalent directions of the Brillouin zone and triggers a subsequent uniform precession. We predict nonthermal magnetization control by tuning the laser frequency and polarization direction. Our mechanism explains recent ultrafast pump-probe experiments.
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