Synopsis

Gravitational wave detectors have reached the thermodynamic limit of optical coatings. Further sensitivity improvements require new coating materials and noise mitigation techniques. This project models the behaviour of higher order spatial laser modes in optical resonators for measuring coating thermal noise directly.

Research fields

Materials Science and Engineering;Photonics, Lasers and Nonlinear Optics

Required background

Computational skills (e.g. Python, MATLAB) are recommended. Knowledge of finite element software or methods is useful but not required. The project scope can be adjusted according to student level.

Description

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 detectors have reached the thermal noise limit of optical coating technology: thermodynamic effects within the mirror coatings drown potential signals. This has sparked a broad search for novel coating materials and mitigating technologies. The use of cryogenically cooled silicon mirrors and 2µm wavelength lasers is a very promising avenue towards substantial sensitivity improvements.

Your goal in this project is to model the coupling efficiency of a laser into an optical resonator formed by two or more mirrors for a cryogenic coating noise experiment.  You will also investigate the overlap of laser spatial modes with mechanical eigenmodes of the mirrors to understand their different coupling to thermodynamically driven fluctuations in the mirrors.

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).