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DS: Fachverband Dünne Schichten
DS 20: Poster
DS 20.31: Poster
Donnerstag, 12. März 2026, 18:30–20:30, P2
Investigating the Anisotropy of Optical Phonons in Ultrafast Optical Pump-Probe Experiments — •Felix Nöhl1, Felix Hoff1, Jonathan Frank1, and Matthias Wuttig1,2 — 1I. Institute of Physics (IA), RWTH Aachen University, Germany — 2Peter Grünberg Institute - JARA-Institute Energy Efficient Information Technology (PGI-10), Jülich, Germany
Phonons are quantized lattice vibrations closely linked to bond strength and atomic arrangement. A well-established tool to study incoherent optical phonons in frequency domain is Raman scattering. Ultrafast lattice dynamics and coherent phonons, capable of modulating macroscopic physical properties, are of interest to emerging research fields. In ultrafast optical pump-probe experiments, coherent optical phonons can be excited and directly measured in the time domain via transient changes in reflectivity. Due to their pronounced phononic response, bismuth and tin selenide were used to further explore the excitation and detection of coherent phonons. A pump polarization scheme for our optical pump-probe setup was implemented and polarization resolved pump-probe and Raman measurements compared. Clear symmetries were observed, highlighting the influence of the lattice structure. This improves our understanding of coherent phonon anisotropy in optical pump-probe measurements and enables modulation of the detected signal by changing the pump polarization.
Keywords: Coherent Phonons; Pump-Probe; Anisotropy; Bismuth