Dresden 2017 – scientific programme

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DS: Fachverband Dünne Schichten

DS 28: Focussed Session: Oxide Semiconductors for Novel Devices I

DS 28.6: Topical Talk

Wednesday, March 22, 2017, 11:15–11:45, CHE 89

Exceptional Points in Oxide Bulk and Metamaterials — •Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, D-04103 Leipzig

The spectral dispersion of exceptional points (singular optic axes) is measured for (monoclinic and thus biaxial) β-Ga₂O₃ bulk material in the absorption regime. Also we show that exceptional points exist in fully transparent, optically ’effectively’ biaxial, anisotropic micro-cavities, fabricated using an uniaxial cavity material with its axis inclined to the Bragg mirror growth direction. Here the lack of time reversal symmetry is mediated by the mode broadening, i.e. the photon escape from the – in principle – open cavity system. As a consequence the eigenmodes are generally elliptically polarized, and completely circularly polarized eigenmodes are expected in certain directions. Via geometric and chemical composition design degrees of freedom, the spectral and angular position of these chiral modes can be rationally designed. Thus circularly polarized emission becomes possible without the use of spin injection or internal or external magnetic fields.