PhD. Tobias Huber, Institut für Experimentalphysik, Universität Innsbruck

Title: Time-bin entangled photons from a quantum dot

Abstract:

In my research, I investigate different aspects of quantum dots as photon sources. Reaching from the quality of the emitted photon state over optimization of the excitation process to the generation of entangled photon pairs.

In this talk I will motivate why single entangled photons are useful for quantum communication. Further, I will introduce semiconductor quantum dots as sources of single photons and entangled photon pairs. Then, I will show how we use a coherent excitation process to produce time-bin entangled photons and I will explain how to analyze time-bin entanglement. Time-bin entanglement is needed to transmit entangled photons through fiber networks, because polarization entanglement will suffer from the so-called polarization mode dispersion. Furthermore, it is straightforward to extend the scheme (with a suitable quantum dot) to produce hyper entangled photon pairs, which are entangled in polarization and time-bin at the same time. Hyper entanglement can be used for dense coding, complete Bell state measurements or dense teleportation protocols.