Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 36: Poster Ib
HL 36.37: Poster
Dienstag, 8. März 2016, 15:00–19:00, Poster A
Nonlinear Phononics and the interaction of Light and Phonons — •André Bojahr1, Matthias Rössle1, Wolfram Leitenberger1,2, Peter Gaal2, Mathias Sander1, Matthias Reinhardt2, Alexander von Reppert1, Jan-Etienne Pudell1, and Matias Bargheer1,2 — 1Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany — 2Helmholtz-Zentrum Berlin, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany
Phonons are often regarded as delocalized quasiparticles with certain energy and momentum. The anharmonic interaction of phonons determines macroscopic properties of the solid, such as thermal expansion or thermal conductivity, and a detailed understanding becomes increasingly important for functional nanostructures. By the use of ultrashort laser pulses we are able to excite monochromatic phonon wave packets with a wavelength in the nanometer range. To observe the anharmonic interaction of these phonons we use time-resolved Brillouin scattering with a white light probe pulse and ultrafast X-ray diffraction. [1] With these methods we were able to observe the nonlinear mixing of a narrowband coherent phonon wave packet in strontium titanate (SrTiO3) to its second harmonic. [2] Furthermore, we present concepts to amplify monochromatic phonons by stimulated Raman scattering to overcome the limits of the maximum phonon amplitude in the excitation process mainly given by the damage threshold due to ultrafast heating above the melting temperature. [1] Opt. Express, 21, 18, 21188-21197 [2] Phys. Rev. Lett., 115, 195502