PhD defence by Andreas Dyhl Østerkryger

Title:  Engineering of nanophotonic structures for quantum information applications

Supervisors:
Principal supervisor: Assoc. Prof. Niels Gregersen, DTU Fotonik
Co-supervisor: Professor Jesper Mørk, DTU Fotonik

Evaluation Board:
Assoc. Professor Andrei Lavrinenko, DTU Fotonik
Post Doc Philip Trøst Kristensen, Humboldt-Universität zu Berlin, Germany
Head of Research Group Sven Burger, Zuse Institute Berlin, Germany

Master of the Ceremony:
Assoc. Prof. Søren Stobbe

Abstract:
 Various nanophotonic structures are studied theoretically using the Fourier modal method (FMM), including ridge waveguides, 2D photonic crystals and nanowires.A FMM with open boundary conditions in Cartesian coordinates is developed, implemented and tested. We find that an efficient sampling of the k-space leads to faster convergence as compared to the standard equidistant sampling.A photonic crystal waveguide side-coupled to a microcavity and embedded with a partially transmitting element (PTE) is investigated. We demonstrate how the symmetry of the Fano-shaped transmission spectrum is controlled by the PTE-cavity distance.All-optical mapping of the position of single quantum dots embedded in tapered nanowires is demonstrated. We show that the far-field patterns of the quantum dots reveal their lateral position. Next, we consider a truncated nanowire placed on a mirror using a single-mode model and a model including all optical modes. We identify a breakdown of the single-mode model in computing both the Purcell enhancement and the source efficiency. Simple physical explanations of this breakdown are provided.Finally, a quantum dot placed in a Fabry-Perot cavity formed by two mirrors embedded in a waveguide is investigated. We develop a quantum mechanical model, which correctly accounts for both the cavity and the waveguide effects, and we predict simultaneous high indistinguishability and efficiency to be achievable in long Fabry-Perot cavities.

Time

Thu 23 Aug 18
13:30 - 16:30

Organizer

DTU Fotonik

Where

Lyngby Campus
Building 341, aud. 22