Periodic Reporting for period 1 - TOPOPOLIS (Topological Polaritons in Semiconductor Photonic Crystal Structures: Exotic band structures and topological polariton states for quantum simulation and future optoelectronic devices)
Reporting period: 2016-03-01 to 2018-02-28
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.
In a Lieb-lattice geometry, that shares some distinct features with the honeycomb lattice, we have observed condensation in S- and P-band flatband states. Within a careful investigation of the properties of micropillars - the building blocks for lattice potential structures - results on polariton propagation behavior and the temporal coherence of trapped polariton condensates have been published.
In a significant technical advance, we have been able to demonstrate that polaritons in lattices can, in addition to laser excitation, also be excited (and potentially be tuned) electrically by doping and contacting polariton lattices. Finally, experiments on polariton lattices under magnetic field have shown first hints of polariton edge modes that might lead to a full demonstration of a polariton topological insulator.
Results have been published in peer-reviewed journals and have been made available on open access platforms, such as arXiv.org. In addition, results have been presented and discussed on international conferences and workshops.