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HL: Fachverband Halbleiterphysik
HL 16: Microcavities
HL 16.10: Vortrag
Montag, 14. März 2011, 17:00–17:15, FOE Anorg
ZnO mesa-structures in planar microcavities — •Helena Hilmer, Chris Sturm, Steve Linke, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig
The realization of Bose-Einstein Condensation (BEC) above room temperature in ZnO-based microresonators is still a topic of dedicated research. These systems offer both interesting physics as well as desirable applications. Until now we have observed our microresonators to be in the strong coupling regime up to 410 K [1].
Our microresonators have been grown on c-sapphire substrates by means of pulsed laser deposition. They consist of a ZnO-cavity as active medium, with an optical thickness of half a medium wavelength, that is sandwiched between two all-oxide Bragg reflectors (BR). Yttria stabilised zirconia and Al2O3 have been chosen as BR materials. In contrast to former samples, the cavity layer was structured with circular mesas of diameters ranging from 10...100 µm with a depth of only a few nanometers by photolithography and subsequent etching in highly diluted phosphoric acid. This leads to a blueshift of the uncoupled cavity-photon mode energy of about 20 meV in the etched area surrounding the mesa and therefore also to a shift of the lower polariton branch. The impact of such mesa as trap for polaritons and the effect on the polariton population is investigated.
[1] C. Sturm et al., New. J. Phys. 11, 073044 (2009).