Dresden 2020 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 15: Postersession KFM

KFM 15.8: Poster

Thursday, March 19, 2020, 16:00–18:30, P2/1OG

Fs-pump-supercontinuum-probe absorption spectroscopy of small polarons in polar oxide crystals — •Anton Pfannstiel, Andreas Krampf, and Mirco Imlau — University of Osnabrueck, Department of Physics, Barbarastrasse 7, 49076 Osnabrueck, Germany

Spectroscopy of small polaron absorption on the sub-ns timescale is commonly performed using probe pulses at distinct wavelengths. As small polaron absorption bands in polar oxide crystals with a rich defect structure are very broad and often superpose, transient absorption kinetic traces can usually not unambiguously be assigned to individual small polaron species. Furthermore, their distinct absorption bands naturally remain unresolved.

We thus have developed a fs-pump-supercontinuum-probe spectrometer enabling the investigation of small polaron absorption from the visible (VIS) to the near-infrared (NIR) spectral region with sub-ps temporal resolution. As a unique feature different crystals for supercontinuum probe generation and a joint VIS-NIR-spectrometer are combined.

Using the setup, we successfully studied transient absorption of various polar oxide crystals such as LiNbO₃, LiTaO₃ and LiNb_1−xTa_xO₃, etc. We discuss our findings in the well-established framework of small polaron absorption. Financial support by the DFG (IM37/11-1) is gratefully acknowledged.