Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 37: Plasmonics and Nanooptics 1
O 37.5: Talk
Wednesday, September 7, 2022, 11:45–12:00, H3
Near-field imaging of hyperbolic shear polaritons in gallium oxide — •Sören Wasserroth1, Joseph R. Matson2, Xiang Ni3, Giulia Carini1, Katja Diaz-Granados2, Maximilan Obst4, Enrico Maria Renzi3, Emanuelle Galifi3, Susanne Kehr4, Lukas M. Eng4, Martin Wolf1, Thomas G. Folland5, Andrea Alu3, Joshua D. Caldwell2, and Alexander Paarmann1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — 2Vanderbilt University, Nashville, USA — 3City University of New York, New York, USA — 4Technische Universität Dresden, Dresden, Germany — 5University of Iowa, Iowa, USA
Controlling the propagation direction and other properties of light in a material and at an interface is a very active field in current research. Strong anisotropy in crystals can lead to a hyperbolic dispersion featuring coupled light-matter interactions known as polaritons with highly directional propagation. Recently [1], it was shown that the additional anisotropy in monoclinic crystals, such as beta phase gallium oxide (bGO), gives rise to tilted wave fronts and asymmetric responses, called hyperbolic shear polaritons (HShPs).
Here, we will show mid-infrared free electron laser based near-field imaging of HShPs in bGO. Gold discs are used as local emitters on the bGO substrate. By changing the IR wavelength we observe the rotation and asymmetry of the HShPs. We compare the obtained images to simulated near-field contributions.
[1] Passler et al., Nature 602, 595 (2022)