Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 27: Spin-Dynamics, Magnetization Reversal II
MA 27.9: Vortrag
Donnerstag, 30. März 2006, 12:15–12:30, HSZ 403
Phase-sensitive Brillouin light scattering spectroscopy — •T. Schneider1, A. Serga1, B. Hillebrands1, and S. Demokritov2 — 1Fachbereich Physik, TU Kaiserslautern, 67663 Kaiserslautern — 2Institut für Angewandte Physik, Westfälische Wilhems-Universität, Münster
We report on the first implementation of phase sensitivity into Brillouin light scattering (BLS) spectroscopy. Combined with a time- and space-resolved BLS setup this allows for access to quantities such as the phase profile and the wave front of spin wave packets and beams. In order to access phase information, interference between the light inelastically scattered by the spin wave under investigation and a frequency shifted coherent reference beam was used. Designing an optical interferometer setup, mechanical and thermal stability is of paramount importance to yield reliable phase information. We have solved the problem of stability by spatially combining the optical reference and the signal beam along one single axis. To achieve the necessary frequency shift of the reference light, a microwave electro-optical resonance modulator based on a Lithium Niobate single crystal was constructed. As this modulator is driven by the same microwave source that is used for the excitation of the spin waves, coherency between the frequency shifted and the inelastically scattered light guaranteed. The measurements of dipolar dominated spin waves in ferrite films clear demonstrate a phase structure of the spin wave packets. Phase fronts are clearly visible. The measured values of the wavelength corresponds well with the calculated one.
Financial support by the DFG is acknowledged.