Ultrafast spectroscopy of coupled quantum dots: quantum dot - particle plasmon and quantum dot - quantum dot coupling

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A single quantum dot as a solid-state implementation of an atom-like system can be used as asingle-photon source or as a qbit for quantum computing. However, the later application willrequire interfacing the quantum dot to other systems like neighbouring quantum dots (forquantum computing) or plasmonic structures (to transport signals on the nano-scale). Thewell-controlled coupling by exact positioning of quantum structures is subject of the wholefocused research group. As the intrinsic time constant of a quantum dot's optical excitation isin the order of some 100 picoseconds a natural method to investigate the desired coupling isultrafast optical spectroscopy, which is the subject of this project. It is our goal to answer thefollowing and related questions: Is it possible to use laterally coupled quantum-dot molecules(project 5) as quantum gates? Can we switch the coupling between hyperfine-splitted excitonlines using vertically stacked quantum dots (project 6) on a picosecond timescale? Is it possibleto couple epitaxially grown quantum dots to plasmonic nanoantennas (project 4) withoutquenching the luminescence? We will apply pump-probe spectroscopy and time-resolved single-photon counting on a single nanoobject level to find the answers.