TOPOPOLIS · Topological Polaritons in Semiconductor Photonic Crystal Structures: Exotic band structures and topological polariton states for quantum simulation and future optoelectronic devices

Topological Polaritons in Semiconductor Photonic Crystal Structures: Exotic band structures and topological polariton states for quantum simulation and future optoelectronic devices

This project aimed at the fundamental understanding and realization of topologically protected edge modes in a hybrid light-matter system. These hybrid states are so-called exciton-polaritons, hosted by technologically well-developed semiconductor structures. Topological insulators are a class of materials in which topological invariants lead to a robustness against perturbations. Probably the most striking feature is the emergence of topological edge states at the boundary areas with distinct topological invariants. The measurable physical effect is robust, unidirectional transport, unaffected by disorder or defects. Topological insulators have for the fist time been observed in the integer quantum Hall effect, meaning in electron transport physics. Since then, manifestations of topological effects have been demonstrated in a wide range of field, including cold atoms, acoustics, mechanics, microwaves and notably photonic systems. Topological insulators have been proposed theoretically for exciton-polaritons in lattice potential landscapes, such as e.g. the honeycomb lattice. The striking advantage of using a system that is part-light, part-matter is that the light part allows for propagation and the system to be measured by spectroscopy techniques, while the matter part allows for interactions, manipulation and is susceptible to magnetic fields. The overall objectives of this fellowship, next to the mutual exchange of knowledge, is the epitaxial growth and processing of semiconductor microcavity landscapes, the subsequent spectroscopical investigation, all towards the final goal of a polariton topological insulator. During the 24 month project period the MSCA Fellow Sebastian Klembt and the host institution, the TEP group lead by Prof. Höfling have intensely shared knowledge and ideas regarding sample preparation and device technology, experiment design and spectroscopic methods. We have made advance in the control of polariton lattice structures leading to publications, demonstrating Flatband- and Dirac-cone dispersions, typical for honeycomb- and Lieb-lattice geometries. Furthermore we have studied and published on the propagation behavior and condensation dynamics of polaritons in confined structures, which are important pre-requisites for polariton topological insulators. Final experiments on polariton honeycomb lattices under magnetic field have shown first hints of polariton edge modes that might lead to a full demonstration of a polariton topological insulator. The collaboration has been highly beneficial for both sides and we firmly believe that the mutual support has been crucial for the success of the project.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз