Andreas Freise :: PhD Projects

PhD Projects

Within the scope of my research activities I am currently offering the PhD projects listed below. In my group we develop new laser interferometer experiments in our laboratories; we work on the design and development of the large-scale laser interferometers for gravitational wave detection such as Advanced LIGO and we develop new numerical simulations to support these experimental activities. Our video paper on the development of Laguerre-Gauss modes shown below gives a good overview of our work, it shows the members of my group, a glimpse into one of our labs and some simulation results. Have a look:

Jove Video Paper, Screenshot

If you are excited by projects that bring theoretical understanding and experimental physics together, please contact me. For more information (e.g., how to apply) please see also the Gravitational Wave group's PhD admissions page.

Note that the descriptions below describe the overall context, the project details will be decided with the students later on. All students working on the following projects will have the unique opportunity to support the current graviational wave detectors such as Advanced LIGO, which are expected to make the first ever direct detection of a gravitational wave within the time frame of the student project!

Optical design and control of multi-interferometer instruments

Start date October 2014, funded by ASPERA (UK and EU students)

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 gravtional wave detector, the Einstein Telescope (ET). ET will be able to produce a constant stream of data for astronomical analysis. To achieve this, the detector will have an enlarged bandwidth using the Xylophone approach employing several co-located interferometers tuned to different bands of the full spectrum. Further advantages can be achieved by using other co-located schemes, such as the Triple Michelson layout.

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 investigate interferometers with new digital signal processing schemes to study the feasibility of such systems and to optimise their performance. This project includes experimental work in the laboratory on prototype interferometers as well as theoretical investigations using computer models.

Laser beam shape distortions and quantum effects

Start date October 2014, funded by a European Marie Curie Initital Trainign Network (non-UK students)

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 the advanced detectors 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.

The specific objective of this project is to perform a new implementation of an optical simulation code that allows to perform accurate prediction of mirror surface effects as well as the photon quantum effects. The model shall be implemented using GPU-based algorithms making the software accessible to experimentalists and designers for rapid prototyping of new optical technologies. The main focus of this project is on the implementation and use of numerical methods, however, the project can involve experimental work in laser optics as well as theoretical investigations in quantum optics and classical optics.

Advanced Technologies for Gravitational Wave Detectors

Start date October 2014, STFC studendship (UK students)

The detection of gravitational waves is currently one of the most challenging tasks in experimental physics. After several decades of development in interferometric detectors, the next generation is expected to reach the sensitivity required for a direct detection of gravitational waves. Some of the large laser interferometers (LIGO, GEO, VIRGO) have completed their data taking periods looking for gravitational waves, without achieving the long awaited first direct detection. Now the next generation of detectors with more than sufficient sensitivity is already under construction. The Advanced LIGO project (United States) is well underway and our group takes part in this exciting project.

At the same time we conduct lab-based research on new optical technologies which could be used to upgrade the interferometric detectors in the future. Past projects included the use of ring-shaped laser modes (see this and this paper), the experimental demonstration of diffractive optics or displacement noise free interferometry (see e.g. this article). This is a unique opportunity to study modern laser optics and to develop instruments or concepts that will be employed to improve the science reach of one of the most exciting international large-scale experiments.