Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 8: Crystallography in Materials Science, Microstructure and Dielectric Properties

KFM 8.1: Vortrag

Montag, 5. September 2022, 15:00–15:20, H7

In Situ Structural and Optical Characterization of Laser Recrystallization in an Ultrafast TEM — •Jakob Hagen, Murat Sivis, and Claus Ropers — Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany

Surface-plasmon resonances (SPR) have gained increasing attention due to their widespread use in various scientific fields [1]. These resonantly excited collective free-electron oscillations are able to localize and enhance electromagnetic fields beyond the diffraction limit [2]. To this date, the fabrication of such structures with high optical quality remains challenging, since in general, bottom-up-approaches suffer from the poly-crystallinity of the metal which counteracts the plasmon propagation by damping at grain boundaries [3]. In this study, we created plasmonic nanodiscs by electron beam lithography (EBL) and subsequently performed in situ annealing with a pulsed laser source in an ultrafast transmission electron microscope (TEM). This method allows for live-tracking of the boundary migration and also for characterization of SPRs by photon-induced near-field electron microscopy (PINEM) [4]. Upon illumination, the number of grains reduces drastically leading to almost perfect mono-crystals while preserving the shape. Our approach combines the benefits of mono-crystalline plasmonics [5] with nanometrically precise positioning from EBL.

[1] S. Lal et al., Nat. Photonics 1, 641-648 (2007), [2] K. B. Crozier et al., J. Appl. Phys., 94, 4632 (2003), [3] M. Bosman et al., Sci. Rep. 4, 5537 (2014), [4] L. Piazza et al., Nat. Commun. 6, 6407 (2015), [5] J.-S. Huang, Nat. Commun., 1:150 (2010)