CGA Summer Program

Published in the Research School of Physics Event Horizon
Vol50 Issue45 10–14 November 2025

Projects on offer:

Exploring all things standard sirens
(Dr Liana Rauf)

Standard sirens are compact binary mergers that emit gravitational waves, which are used to measure the expansion rate of the Universe known as the Hubble constant. An independent measure of the luminosity distance from the gravitational wave signal, combined with the source’s host galaxy redshift can provide us a measure of the Hubble constant. Unfortunately, we are limited by observations and systematic errors to determine a precise measurement. This is where the power of simulations can come into play! Using the plethora of public tools available we can study populations of simulated mergers, their astrophysical properties and how they correlate with host galaxies. This will allow us to understand what the limitations of current models are and where we need to improve the techniques to measure the Hubble constant.

Characterisation of photodiodes suitable for a 2um squeezed light source 
(Dr Terry McRae, Dr Jiayi Qin)

This project investigates the performance of photodiodes for detecting 2-µm squeezed light, a promising approach to surpass quantum noise limits in precision optical measurements. Using a stabilized optical setup developed at the Australian National University, the work focused on optimizing cavity locking, dual resonance, and nonlinear-gain calibration to achieve low optical loss and reliable performance. Several commercial photodiodes were characterized for quantum efficiency (QE) and dark noise, leading to the identification of the Thorlabs FD05D as the most suitable candidate with a QE of around 84%. This project will implement the diode in the homodyne detector and calibration the squeezing level.

Laser Stabilisation based on optical fibre for Inter-spacecraft laser links
(Dr Andrew Wade, Prof. Kirk McKenzie)

The goal of this project is to explore thermal isolation options for fibre optical laser stabilization systems. Such systems may be the future of laser stabilizaiton for Inter-satellite laser interferometers missions used to measure Earth's water move (like the GRACE missions) and Gravitational Waves from supermassive blackholes (like the LISA mission).