Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 4: Quantum dots and wires: Optical properties I

HL 4.5: Vortrag

Montag, 12. März 2018, 10:30–10:45, EW 201

Unusual transitions in a QD induced by spatially structured laser beams — •Matthias Holtkemper, Doris E. Reiter, and Tilmann Kuhn — Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

The discrete states in semiconductor quantum dots (QDs) can be used to implement proposals from quantum information processing. We show in this contribution, that the optical control of QDs can profit from the excitation using spatially structured laser beams, such as Bessel or Hermite-Gaussian beams, by enabling the optical access to otherwise geometry-forbidden transitions. To be specific, we study selection rules induced by Bessel beams of a topological charge up to two within an analytical QD model. Next, we expand our model by including Coulomb interactions and valence band mixing within a configuration interaction approach. A weakening of the strict selection rules and thereby an increased number of addressable exciton states is found. We discuss the influence of the beam shape by a comparisons between Hermite-Gaussian and Bessel beams, the influence of a positioning of the beam axis away from the QD center and differences in absorption for differently charged QDs. In summary, we present an overview about the new possibilities that arise from QD excitations with spatially structured laser beams.