SKM 2021 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 5: Topical Session Interface Dominated Phenomena - Poster

MM 5.11: Poster

Tuesday, September 28, 2021, 10:00–12:45, P

Large scale process for adjustable resonances as a versatile platform for SERS — •Marcel Below and Jörg Schilling — Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06108 Halle, Germany

Samples on cm²-scale with hexagonal lattices of gold nanoscatterers were created with different controlled periods by using three-beam interference lithography. The resulting nanoscatterers have an elliptical shape and the size of their semi-axes is linked to the period of the lattice.

Spectral transmission measurements show two broad drops of transmission at different wavelengths depending on the polarization of the light. These are identified as single particle plasmonic resonances and can be shifted from the visible to the mid-IR with increasing size of the nanoscatterers. FEM simulations reveal that both plasmonic resonances are caused by the shape of the individual nanoscatterers.

Additionally, considerably sharper and asymmetric drops of transmission, known as Fano resonances, were observed. These Fano resonances are caused by an overlap of the single particle plasmonic resonance of each nanoscatterer and the collective response of the lattice.

When a sample is immersed in a solution of 4-MBA molecules, the molecules bond to the surface of the gold nanoscatterers. Subsequent Raman measurements show a clear SERS signal and a strong dependency on the polarization of the excitation laser. These results present a possible route for large area SERS substrates with tunable plasmonic resonances.