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HL: Fachverband Halbleiterphysik

HL 64: Poster II

HL 64.51: Poster

Donnerstag, 19. März 2020, 10:00–13:00, P1A

Manipulation of exceptional points in planar anisotropic photonic structures — •E. Krüger¹, C. Sturm¹, S. Richter^1,2, J. Zúñiga-Pérez³, H.-G. Zirnstein⁴, L. Trefflich¹, C. Deparis³, B. Rosenow⁴, R. Schmidt-Grund^1,5, and M. Grundmann¹ — ¹Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Germany — ²ELI Beamlines/Fyzikální Ústav AV CR, Czech Republic — ³Université Côte d’Azur, CRHEA-CNRS, France — ⁴Universität Leipzig, Institut für Theoretische Physik, Germany — ⁵TU Illmenau, Leipzig, Institut für Physik, Germany

We present different approaches for establishing exceptional points (EP) in planar dielectric microcavities with broken cylindrical symmetry, realized by using anisotropic cavity layer materials.

Such EPs represent non-Hermitian degeneracies in momentum space, related to a local complex-square-root topology of the resonator eigenenergies. The eigenmodes coalesce along these directions, yielding degeneracy in energy, broadening and polarization.

We prove the exceptional-point nature experimentally and theoretically for ZnO-based microcavities by monitoring the square-root topology around such an EP. Furthermore, we show how the crystal symmetry and the crystal orientation of the cavity layer material as well as the geometrical cavity design influence the occurence and the position of the EPs in momentum space. We discuss also different approaches for breaking the system reciprocity in the cavity plane, thereby paving the way for topological non-trivial photonic systems.

[1] S. Richter et al., Phys. Rev. Lett. 123 (2019)