Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.17: Poster

Donnerstag, 26. März 2009, 15:00–17:30, P2

Collective fluorescence of quantum dot molecules and arrays — •Anna Sitek^1,2 and Pawel Machnikowski¹ — ¹Institute of Physics, Wroclaw University of Technology, Wroclaw, Poland — ²Institute for Theoretical Physics, Technical University of Berlin, Berlin, Germany

The optical properties of quantum dot molecules (QDMs) are affected by collective interaction of the QDs with radiation modes. In atomic systems, such collective effects lead to pronounced superradiant fluorescence [1]. Superradiance has also been observed in a QD sample [2]. In contrast to a gas of atoms, the properties of QDs are never exactly uniform. On the other hand, QDs can be arranged in regular arrays.

In this presentation, we study the collective interaction of excitons in closely spaced QDMs and small arrays of nearly identical QDs with electromagnetic modes. We discuss how collective fluorescence builds up in the presence of a small mismatch of the transition energy and study the resulting optical properties (decay of luminescence) of quantum dot molecules. It turns out that the collective effects are very sensitive to the difference between the dots but coupling between the dots may stabilize the collective fluorescence if the dots are arranged in a regular way [3].

[1] M. Gross et al., Phys. Rep. 93, 301 (1982).

[2] M. Scheibner et al., Nature Physics 3, 106 (2007).

[3] A. Sitek et al., Phys. Rev. B 75, 035328 (2007).