Regensburg 2025 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 72: Poster Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy

O 72.10: Poster

Mittwoch, 19. März 2025, 18:00–20:00, P2

Self-organized plasmonic particles configurations in front of mirror — •Aleksei Overchenko and Frank Cichos — Leipzig University, Peter Debye Institute for Soft Matter Physics, Linnéstr. 5, 04103 Leipzig

Plasmonic particles and their field enhancement properties found wide applications in various fields. For example, they are used in Surface-Enhanced Raman Spectroscopy (SERS), plasmon-enhanced fluorescence, Photothermal Therapy and energy conversion. Field enhancement can be achieved by bringing two spheres into close proximity, placing a sphere on a mirror, fabricating bowtie antennas, or designing hybrid structures like particle-dielectric-mirror systems. In most cases, surface functionalization often requires complicated modification methods such as lithography and chemical binding, e.g., of DNA origami which leads to complicated and non-reconfigurable systems. Here, we deliberately manipulate induvial as well as multiple gold particles in front of a gold mirror by local laser-induced temperature fields generating thermo-osmotic flow. Multiple particle trapping is performed by focused laser that can divide in multiple independent beams via AOD. We characterize the resulting single, dimeric and higher order clusters, their plasmonic coupling and the coupling of the particles to a thin gold film by scattering spectroscopy. The distance between the film and particles is around 10 nm due to the second minimum of the DLVO-theory. Enhancement is described by sensing of biomolecules. The system is reconfigurable as no binding is required and analytes may be bound to the film to enable spatially resolved SERS.

Keywords: Gold particles; Coupling; Gold mirror; Scattering spectroscopy; Without binding