SKM 2021 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 4: Poster

DS 4.4: Poster

Dienstag, 28. September 2021, 10:00–13:00, P

Strong coupling of Bloch Surface Waves and excitons in ZnO up to 430 K — •Sebastian Henn, Marius Grundmann, and Chris Sturm — 1Universität Leipzig, Faculty of Physics and Earth Sciences, Felix-Bloch institute for solid state physics, Linnéstr. 5, 04103 Leipzig, Germany

Exciton-polaritons are bosonic quasi-particles consisting of a cavity photon and an electron-hole pair, exhibiting interesting physical phenomena like Bose-Einstein condensation [1]. Of special interest are exciton-polaritons in semiconductors with large exciton binding energies, where the strong coupling is observable above room temperature [2]. We report here on the experimental observation of the strong coupling between ZnO excitons and Bloch Surface Waves (BSW) up to 430 K. The sample consists of a Bragg reflector and a thin ZnO top layer. This system holds several advantages compared to exciton-polaritons in conventional microcavities: high propagation lengths due to the low loss BSW with large in-plane wave vector, a reduced complexity of production and direct access to the mode-supporting surface layer. In combination with a stable operation at high temperatures, this is of interest for the development of integrated optics devices. By means of a prism coupler in reflection geometry the polariton dispersion was observed and analyzed. We determined the temperature dependent coupling strength, exciton energy and dielectric background.

[1] J. Klaers et al., Nature 468, 545-548 (2010)

[2] C. Sturm et al., New J. Phys. 11, 073044 (2009)