Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 2: 2D Materials and Heterostructures: Photonic Aspects

HL 2.12: Talk

Monday, March 18, 2024, 12:30–12:45, EW 201

Tunable All-Graphene Metasurfaces Based on Bound States in the Continuum — •Michael Hirler, Thomas Weber, Jonas Biechteler, and Andreas Tittl — Chair in Hybrid Nanosystems, Ludwig-Maximilians-University Munich, Germany

We present an all-graphene optical metasurface based on Bound States in the Continuum (BICs). While graphene excels with tunable, long-lived plasmons with outstanding near-field confinement in the mid-infrared, the physics of BICs allows for the generation of spectrally narrow resonances with precise control over the radiative loss channel. This can be achieved by means of patterning monolayer graphene at subwavelength dimensions in various asymmetric structures. Furthermore, the incorporation of a bottom gate separated by an insulating layer allows for electric gating and, thus, the post-fabrication tuning of the plasmonic response. In particular, leveraging the tunability via asymmetric gating opens a new gateway for dynamic control of light-matter-interaction. On the basis of numerical simulations, we discuss the potential and limits of these metasurfaces, while progresses and challenges in realizing a first prototype via electron beam lithography are also outlined. Our metasurface constitutes a promising platform for compact, affordable point-of-care applications such as optical biosensors.

Keywords: Graphene; Bound States in the Continuum; Optical Metasurfaces; Tunability; Nanophotonics