Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 67: Poster: Oxide, Insulator and Semiconductor Surfaces
O 67.11: Poster
Mittwoch, 20. März 2024, 18:00–20:00, Poster C
Sum-Frequency Generation Spectro-Microscopy in the Reststrahlen Band of Wurtzite-type Aluminum Nitride — •Dorothée Mader, Richarda Niemann, Martin Wolf, Sebastian Maehrlein, and Alexander Paarmann — Fritz Haber Institute of the Max Planck Society, Berlin, Germany
Non-centrosymmetric materials including ferroics are commonly studied by second-harmonic imaging.1 This method is highly sensitive to the material’s symmetry, but is commonly employed non-resonantly. In contrast, infrared-visible (IR-VIS) sum-frequency generation (SFG) spectroscopy is employed resonantly to reveal vibrations, local structure and bonding of the material.2 In SFG, the sample is excited at the IR-resonance and mixed with a non-resonant VIS beam leading to generation of sum-frequency light that is detected in the VIS. SFG benefits from the resonance but typically lacks spatial resolution. In this work, we combine the benefits of nonlinear optical imaging and SFG spectroscopy by employing SFG spectro-microscopy using the free electron laser of the Fritz Haber institute.3 Specifically, we test the feasibility of our instrumentation for spectroscopy with m-plane wurtzite-type aluminum nitride as a model system. We find the experimental spectra to agree with our theoretical calculations. In the future, this method will provide spatially resolved spectroscopic information in inhomogeneous systems such as ferroics and their domains.
[1] M. Fiebig et al., APL 66, 2906, (1995).
[2] W. Faust et al., PRL 17, 1265, (1966).
[3] R. Niemann et al., APL 120, 131102, (2022).
Keywords: Nonlinear optics; Spectromicroscopy; Reststrahlenband; Aluminium Nitride; Sum frequency generation