On-going Research Activities

Here is listed the current research activities in the Quantum and Laser Photonics group.

Our research is concerned with the understanding and application of light-matter interactions in nanostructures. Present-day nanofabrication techniques allow the simultaneous control of optical modes and electronic states, e.g. by embedding one or several quantum dots in a photonic crystal resonator or waveguide. Such systems display rich physics and may be exploited for the realization of ultra-small lasers and optical switches as well as forming the building block for future quantum computers. We investigate the fundamental interactions and dynamics of these structures using advanced theoretical and numerical techniques and experimentally using state-of-the-art characterization facilities, including femto-second pump-probe techniques.

The research activities group into three themes that you find below. Under each theme you may find detailed descriptions of the ongoing research activities.

You may also have a look at the on-going and completed PhD Projects in our group.

Nanophotonics for Terabit Communications

NATEC We explore the possibilities for realizing integrated III-V semiconductor photonic chips by combining photonic crystal structures and low-dimensional semiconductors, like quantum wells and quantum dots. We aim to understand the physics of key devices like lasers, amplifiers and switches realized in this platform and the possibilities they offer for realizing ultra-low power and ultra-compact photonic chips. The work includes theoretical modeling, design and optimization, fabrication, basic characterization and systems experiments. The activity is supported by Villum Fonden via a Centre of Excellence (NATEC) grant and takes place in close collaboration with the other groups in the Nanophotonics cluster as well as the High-Speed Systems group at DTU Fotonik and the Topology Optimization group at DTU Mechanical Engineering.

Silicon Photonics

We research revolutionary concepts of optoelectronic devices, specifically lasers and detectors, in which III-V active material is hybridized onto silicon-on-insulator (SOI) platform. The research aims to investigate new device physics that can realize lasers with ultimate efficiency and speed, detectors capable of error-free detection of 10s-100s photons, and MEMS-broadband-tunable lasers and detectors. The research activity includes theoretical study and advanced device simulations as well as device fabrication and characterization. Three Ph.D. projects and a national research project (FTP Hi-ECO) are on-going in the activity.

Quantum Information Technology

We investigate the governing physics of solid-state devices for quantum information processing and exploit the resulting knowledge to propose designs for single-photon sources and switches with new functionalities. The main focus is the light-matter interaction at the single or few-photon level in quantum dots with discretized electronic states embedded in photonic crystal membrane-based cavities or waveguides, micropillar cavities and photonic nanowires. This interaction is influenced by the photonic environment through the local density of optical states and by the solid-state environment through phononic lattice vibrations. The work includes the construction of simulation tools for the optical properties based on modal methods, coupled mode analysis and Green's function methods as well as for the microscopic properties of the quantum emitters taking into account non-Markovian effects arising from interactions with the phonon reservoir. We have close collaborations with leading experimental groups in Denmark, Germany and France who are fabricating the proposed devices. The work is supported by the Danish Research Council for Technology and Production as well as the European Association of National Metrology Institutes.

Research Responsibility

NATEC

NATEC is a Centre of Excellence funded by the Villum Kann Rasmussen Foundation to do fundamental research on devices based on quantum dots and photonic crystals for terabit communication systems.