Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 75: Poster IIIB
HL 75.20: Poster
Thursday, March 19, 2020, 15:00–17:30, P2/3OG
Exceptional Points in optical anisotropic semiconductors — •Sebastian Henn1, Evgeny Krüger1, Chris Sturm1, Armin Dadgar2, Matthias Wieneke2, Rüdiger Schmidt-Grund1,3, and Marius Grundmann1 — 1Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Linnéstr. 5, Leipzig — 2Otto-von-Guericke-Universität Magdeburg, Institut für Physik — 3now at: Technische Universität Ilmenau, Institut für Physik, Weimarerstr. 25, Ilmenau
We investigate exceptional points (EP) in optically anisotropic transparent thin films both experimentally and theoretically. EP represent degeneracies in k-space and were already observed in absorptive biaxial crystals [1] and microcavities [2,3]. At the degeneracy the eigenvalues and eigenstates of the system, i.e. the complex energy and polarization, coalesce. This is reflected by a complex square root topology around the EP [2]. Promising systems for the realization of EP are optically anisotropic thin films, providing symmetry breaking and dissipation through losses at the interfaces. We demonstrate the presence of EP in GaN and ZnO thin films using spectroscopic Müller Matrix ellipsometry and presenting rigorous Maxwell-based calculations. We discuss ways to control the occurrence and direction of the EP by altering the design of the system. [1] W. Voigtet al., Ann. Phys 314, 367 (1902) [2] S. Richteret al., Phys. Rev. Lett. 123, 227401 (2019) [3] J. Wiersig, Phys. Rev. Lett. 112, 203901 (2014)