Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Plasmonics and Nanooptics

O 59.9: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-OG1

Polarization resolved microscopy of plasmonic nanoparticles — •Jasmin Schönzart, Markus Pfeiffer, and Klas Lindfors — Department of Chemistry, University of Cologne, Luxemburger Str. 116, 50939 Köln, Germany

The plasmon resonance of metal nanoparticles may be modified by changing the shape or material of the particle or the medium surrounding the nanostructure. Varying the shape of resonant metal nanoparticles allows controlling the optical properties of the structure. Using the polarization of the incident light the excitation of different plasmonic modes can be controlled. This is of great interest, as the localization of the near field enhancement can be controlled on a sub-wavelength scale. Here we present a microspectroscopy setup, which enables interference-contrast microscopy of very small plasmonic nanostructures using complex polarization states of the incident light such as radial and azimuthal polarization.

In initial experiments we determined the size-dependent interference scattering signal for spherical gold nanospheres down to particle sizes of 20 nm. In further studies we investigated gold nanorods. These show a longitudinal- and transversal plasmon mode, which can be excited separately, depending on illumination wavelength and orientation of the polarization with respect to the nanorod axis.We further show some first results on measurements with radial and azimuthal illumination polarizations. Here magnetic and electric modes of higher order can be excited.