Regensburg 2022 – scientific programme

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SYQM: Complexity and Topology in Quantum Matter

SYQM 1: Complexity and Topology in Quantum Matter

SYQM 1.4: Invited Talk

Friday, September 9, 2022, 11:15–11:45, H1

Topological photonics and topological lasers with coupled vertical resonators — •Sebastian Klembt — Chair for Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.

Topological Photonics is an emerging and novel field of research, adapting concepts from condensed matter physics to photonic systems adding new degrees of freedom. After the first demonstations of topological photonic insulators, the field has moved on to study and exploit the inherent non-hermiticity of photonic systems and the interplay with their topological nature. In my talk I will discuss novel photonic lattice devices resulting from the coupling of individual vertical III-V semiconductor microresonators. So-called exciton-polaritons (hybrid states of light and matter) can emerge in the strong coupling regime. By chosing precise lattice geometries we are able to taylor optical band structures realizing novel photonic lattice. Here, the specific geometry as well as the hybrid light-matter nature allow for ways to break time-reversal symmetry and implement topologically non-trivial systems. Thus we were able to experimentally demonstrate the first exciton-polariton topological insulator, manifesting in chiral, topologically protected edge modes. In order to study topological effects in combination with optical non-linearities, topological lasers have been envisaged and realized. They exploit topological effects to efficiently couple and phase-lock extended arrays of lasers to behave as one single coherent laser. Here, I report on the first experimental demonstration of a topological insulator vertical cavity laser array.