Berlin 2012 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 7: 100 years since the Laue experiment: Topical aspects of diffraction and scattering (Joint Session KR, BP, CPP, DF, GP, MA, MI, MM; related to SYXD)
DF 7.3: Vortrag
Dienstag, 27. März 2012, 10:15–10:30, EMH 225
Brillouin scattering of ultrashort optical and x-ray pulses from quasi-monochromatic phonon wavepackets — •Marc Herzog1, André Bojahr1, Jevgenij Goldshteyn2, Steffen Mitscherling1, Wolfram Leitenberger1, Dmitry Khakhulin3, Michael Wulff3, Ionela Vrejoiu4, Roman Shayduk2, Peter Gaal1, and Matias Bargheer1,2 — 1Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany — 3Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — 4European Synchrotron Radiation Facility, Grenoble, France
We excite a SrRuO3 thin film transducer epitaxially grown on a SrTiO3 substrate with pulse trains of ultrashort laser pulses. Each laser pulse launches single bipolar strain pulses of broad bandwidth into the substrate [1] which coherently add up to form a quasi-monochromatic sub-THz phonon wavepacket. The generation and dynamics of these phonon pulses is investigated by Brillouin scattering using visible and hard x-ray photons. The combination of both methods reveals the excited narrow phonon spectrum as well as the phonon lifetime which is on the order of a few 100 ps in the considered frequency range. This lifetime is explained by anharmonic phonon interactions.
[1] Thomsen et al., Phys. Rev. B 34, 4129 (1986).