Andreas Freise :: PhD Projects

PhD Projects

Within the scope of my research activities I am currently offering the following PhD projects. For further information on individual projects, please contact me. For other related information (e.g., how to apply) please refer to the group's PhD admissions page.

Digital high-precision laser control

Our research group specialises in precision measurements with laser interferometers. We have leading roles in the optical design of large international projects and do tests of new optical technologies in our own laboratory experiments with small prototype laser interferometers. Our current experimental work focusses on reducing measurement noise through coherent detection of multiple optical signals with a digital system.

Our group has been leading the optical design for a new detector, the Einstein Telescope (ET). Future, so-called third-generation, interferometric detectors such as ET will be able to produce a constant stream of data for astronomical analysis. However, with a large number of co-located interferometers, the technical challenges increase, especially regarding the coupling of unwanted noise sources; the draft optical layout of the Einstein Telescope highlights the complexity of such systems. We will use digital signal processing schemes to study the feasibility of such systems and to optimise their performance.

The student joining this project would participate in the design and setup of a new laser interferometer experiment. In particular we will stabilise diode lasers to setup several Michelson interferometers to create a multi-interferometer test system. The sensing and control of all optical signals will be performed with a high-speed digital system, controlled by Labview.

Beam shape distortions and quantum effects

Modern lasers can generate amazingly stable light fields at high powers. This has allowed us to create increasingly more precise interferometers. The largest and most precise laser interferometers today are ground-based gravitational wave detectors. The most advanced of these machines, Advanced LIGO, will start operation in 2015. Our group is involved with the installation of the instrument, using numerical simulations to understand unexpected problems with the optics. At the same time we are investigating new optical technologies in our laboratory which can be used to improve Advanced LIGO in the future. Our group specialises on the optical design to mitigate the effects of beam shape changes, and the quantum optical coupling between the light and the optics.

This project requires experimental work in the laboratory as well as theoretical investigations in quantum optics and classical optics using numerical simulations. The student who works on this project will have the unique opportunity to support Advanced LIGO, which is expected to make the first ever direct detection of a gravitational wave within the time frame of the student project!