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O: Fachverband Oberflächenphysik

O 70: Poster: Plasmonics and Nanooptics II

O 70.6: Poster

Wednesday, March 29, 2023, 18:00–20:00, P2/EG

Enhanced Second Harmonic Generation from Silver Nanoantennas — •Fabian Scheidler, Johanna Klos, Jessica Meier, Luka Zurak, and Bert Hecht — Nano-Optics and Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany

Plasmonic gold nanostructures allow to achieve large field enhancement in nanoscale volumes and are therefore appealing to boost nonlinear processes such as second harmonic generation (SHG). Especially intense near-field hot spots emerge in the gaps of symmetric dimer antennas, yet strong SH sources created in the gap region oscillate out-of-phase and thus destructively interfere in the farfield [1]. Introducing local asymmetry by careful design of the antenna gap geometry allows to mitigate the so-called silencing effect and leads to enhanced SHG [2].
In the ultraviolet-visible spectral range, however, the SH efficiency for gold nanoantennas is limited due to high damping below 500 nm. Here we present silver nanoantennas fabricated from epitaxial grown single-crystalline microplatelets to boost SHG below 500 nm, where silver shows significantly less absorption losses compared to gold. The antenna design is optimised for SHG taking into account the linear scattering response with a resonance at the SH.
[1] J. Berthelot et al., Optics express, 20(10), 10498-10508 (2012).
[2] J. Meier et al., arXiv:221014105 (2022).