PhD defense by Anders Nysteen

Title: Few-photon Non-linearities in Nanophotonic Devices for Quantum Information Technology



Prof. Jesper Mørk, DTU Fotonik



Postdoc Philip T. Kristensen, Humboldt-Universität zu Berlin

Postdoc Dara P. S. McCutcheon, DTU Fotonik

Model Developer Per Kær Nielsen, Blackwood Seven A/S


Evaluation Board

Prof. Kurt Busch, Humboldt-Universitaet zu Berlin

Prof. Andrea Fiore, TU Eindhoven

Assoc. Prof. Martijn Wubs, DTU Fotonik


Master of the Ceremony

Assoc. Prof. Niels Gregersen, DTU Fotonik



In this thesis we investigate few-photon non-linearities in all-optical, on-chip circuits, and we discuss their possible applications in devices of interest for quantum information technology, such as conditional two-photon gates and single-photon sources.

In order to propose efficient devices, it is crucial to understand the non-equilibrium dynamics of strongly interacting photons in detail. Employing both numerical and analytical approaches, we map out the full scattering dynamics for two photons scattering on a two-level emitter in a one-dimensional waveguide. Specifically, for two identical, counter-propagating photons, the emitter works as a non-linear beam splitter, as the emitter induces strong directional correlations between the scattered photons.

We propose two setups for two-photon controlled-phase gates; one using two identical two-level systems and passive optical elements, and another setup using dynamical capture of the first of two temporally separated photons in a non-linear ring resonator.

Semiconductor quantum dots are promising for realizing few-photon non-linearities in solid-state implementations, although coupling to vibrational modes in the surrounding lattice has significant influence on the dynamics. We demonstrate how the influence of longitudinal acoustic phonons on the quantum dot dynamics can significantly be suppressed or enhanced, which is done by tailoring either the electronic or the phononic confinement.


ons 29 apr 15
13:30 - 16:30


DTU Electro


Lyngby Campus

Building 306, auditorium 36