Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 4: Plasmonics and nanooptics: Fabrication and characterization

O 4.2: Talk

Monday, March 12, 2018, 10:45–11:00, MA 041

Tuning the visual appearance of plasmonic metasurfaces by controlled disorder — •Florian Sterl, Thomas Weiss, Nikolai Strohfeldt, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Germany

The optical properties of plasmonic nanoparticle ensembles are not only determined by the particle shape and size, but also depend on the arrangement of the individual nanoantennas. The angle-dependent transmission and reflection characteristics of a rectangular nanoparticle array are strongly influenced by lattice diffraction effects, while these effects are absent in a completely randomized nanoparticle ensemble. By introducing short-range or long-range disorder into a nanoparticle lattice, one can furthermore strongly influence the optical properties.

We attempt to gain a better understanding of the effect of disorder on the bidirectional reflectance distribution function of complex plasmonic metasurfaces through both simulations and experimental characterization. To this end, we treat the nanoantennas as individual dipoles, and simulate the electric field based on dipole-dipole coupling to approximate the optical image one would obtain from nanoantenna arrays with different degrees of disorder. We compare these results to microscope images and spectroscopic measurements on arrays of gold nanoparticles, addressing both the visual image and the angle-dependent characteristics by using a designated back focal plane spectroscopy setup.