Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 60: Plasmonics and Nanooptics: Fabrication, Characterization and Applications I

O 60.5: Talk

Wednesday, March 19, 2025, 11:30–11:45, H8

Optical Response of High-refractive Index Nanodisk Arrays with Hyperuniform Disorder — •Davy Tesch, Koundinya Upadhyayula, Bodo Fuhrmann, Alexander Sprafke, and Ralf Wehrspohn — Martin Luther University Halle-Wittenberg, 06120 Halle, Germany

Light-scattering metasurfaces with tailored disorder, in particular hyperuniform disorder (HUD), have recently attracted interest in the photonics community. HUD promises several properties that were previously associated only with either periodic or random structures. The combination of the strong diffraction of periodic structures and the broadband spectral response of disordered structures holds promise for tailored light scattering.

In this work, we use a scalable fabrication process to experimentally fabricate HUD nanodisk arrays using hydrogenated amorphous silicon (a-Si:H) optimised for low absorption as the nanodisk material. Optical measurements of such fabricated samples show a strong dependence of the scattering response on the form factor of the individual scatterers and their HUD arrangement, given by the structure factor. By tuning these quantities, we were able to tailor the scattering response. One of the most striking results is the ability of the fabricated samples to suppress scattering at small angles (below 45°) due to the HUD arrangement and to enhance scattering at large angles (up to 80°) due to the dominance of electric dipoles in single a-Si:H scatterers.

We have also studied a more complex system: nanodimers consisting of two stacked nanodisks, separated by a spacer layer.

Keywords: hyperuniformity; metasurfaces; nanophotonics; tailored disorder; Mie resonators