Since the beginning of their first observing run in September 2015, the Advanced LIGO and Virgo gravitational-wave detectors have observed multiple merger events of black hole and neutron star binary systems in distant galaxies. These detections teach us about the population, masses, and spins of black holes in the universe, allow tests of strong field dynamics in General Relativity and neutron star equations of state, and enable multi-messenger astronomy with electro-magnetic and neutrino observations. Thermal noise in mirror substrates, optical coatings, and suspensions presents a fundamental limit for the sensitivity of gravitational-wave detectors and the quality of the information we can extract from received signals. The most promising strategies to reduce thermal noise in future detectors involve combinations of new coating and substrate materials, novel coating deposition recipes, larger test mass optics, and cryogenic cooling of the primary mirrors.

This talk will discuss thermal noise in the context of gravitational wave detection. I will give an overview of the design and status of the current detectors and showcase the ANU’s contribution to detector improvements, highlighting the involvement in coatings research.

Johannes Eichholz is a Research Fellow at the Department of Quantum Science at ANU and a member of the ARC Centre of Excellence for Gravitational Wave Discovery OzGrav. He received his PhD from the University of Florida and has worked as a member of the LIGO Laboratory at the California Institute of Technology. He has research interests in gravitational wave detection, precision measurements, thermal noise, optical coatings, and cryogenic interferometry.