PhD Defense by Immo Sollner – Niels Bohr Institute - University of Copenhagen

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Niels Bohr Institute > Calendar > NBI Calendar 2014 > PhD Defense by Immo So...

PhD Defense by Immo Sollner

In this presentation we will focus on the study of quantum electrodynamics in photonic crystal waveguides.  We investigate the interplay between a single quantum dot and the fundamental mode of the photonic crystal waveguide. We demonstrate experimental coupling efficiencies for the spontaneous emission into the mode exceeding 98% for emitters spectrally close to the band-edge of the waveguide mode. In addition we illustrate the broadband nature of the underlying effects, by obtaining coupling efficiencies above 90% for quantum dots detuned from the band edge by as far as 20nm.  These values are in good agreement with numerical simulations.

Such a high coupling efficiency implies that the system can be considered an artificial 1D-atom, and we theoretically show that this system can generate strong photon-photon interaction, which is an essential functionality for deterministic optical quantum information processing.

We present the progress towards the experimental demonstration of a strong photon-photon nonlinearity in resonant transmission experiments and discuss some of the encountered difficulties.

In the final part of this presentation we discuss a novel type of photonic crystal waveguide and show its applications for on-chip quantum information processing. This structure was designed for the efficient mapping of two orthogonal circular dipole transitions to different propagation paths of the emitted photon, i.e. exhibits chiral quantum-dot-waveguide coupling.  Such a structure is ideally suited for a number of applications in quantum information processing and among others an on-chip spin-photon interface, a single photon transistor, and a deterministic cNOT gate.