Gravitational wave detectors are in many ways the most sensitive instruments ever built and have opened a new window to the universe. The steadily growing number of discoveries helps us develop a better understanding of our cosmic setting and probe for exciting new fundamental physics.

Gravitational wave detection has reached the thermal noise limit of optical coating technology: Thermal effects in the mirror coatings drown potential signals in noise. This has sparked a broad search for novel coating materials, coating topologies, and mitigating technologies. One of the most promising avenues towards future gravitational wave detectors is the use of cryogenically cooled silicon mirrors and 2µm wavelength lasers.

Your goal in this project is to design/build a feedback control loop to suppress the frequency and intensity noise of a 2µm wavelength laser that is used in a coating noise experiment. Possible frequency references for this project are optical cavities and fibre-based Mach-Zehnder interferometers. The laser frequency and intensity will be actuated with feedback to the laser diode current, piezo-electric elements, laser temperature, and/or electro-optic modulators. The feedback controller needs to be carefully designed and may use a combination of analog and digital electronics.

The Centre for Gravitational Astrophysics offers a collaborative, diverse, and supportive research environment across the full breadth of gravitational wave discovery. The Centre is a joint effort of RSAA and RSPhys, and hosts a node of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav).

A working knowledge and laboratory experience with optics and lasers as well as electronics is recommended, familiarity with control theory is encouraged. Computational and programming skills (e.g. Python, MATLAB) are preferred. The project scope can be adjusted according to student level.