Dr Aidan Brooks visits Australia

Dr Aidan Brooks (LIGO Laboratory Caltech) visited Australia in Aug-27 through Sep-21 2018 to visit the University of Adelaide (UoA) with additional short trips to UWA, ANU and Monash. The focus of the trip was divided into three main research areas with different time horizons:

• Support for Advanced LIGO for 2018/2019;
• Preparation for A+ (focusing on adaptive optics) - Development for 2019 prototypes and installation 2020-2022;
• Research for LIGO-Voyager - early R&D for deployment around 2027-2028.

Three weeks were spent at the University of Adelaide working with Peter, David, Seb, Daniel, Cao, Alexei, Deeksha and Craig. I worked with Craig to help him improve and simplify his COMSOL model of the optical absorption measurement system. Dan and I worked on developing a realistic Finesse model of Voyager that could be used to simulate intensity and frequency noise coupling through the future interferometer and thus allow us to set noise requirements.
Advanced LIGO support
Extensive discussions were held with Dan and Peter on how Adelaide can continue to support the Hartmann sensor (HWS) code for LIGO. I also discussed the cavity eigenmode modulation (CEM) technique for cavity mode-matching and alignment that Alexei has developed.
A+ preparation
A+ is a medium-scale upgrade to Advanced LIGO (aLIGO) that will introduce frequency dependent squeezing and new coatings to the aLIGO test masses. Much of the trip was focused on development of adaptive optics, designed at Adelaide, for use in A+. Successful deployment of these optics will significantly reduce the complexity of the A+ adaptive optics system and could potentially reduce the budget for this system by $200k or more.
LIGO-Voyager
The third generation of LIGO will be called LIGO-Voyager and will require, amongst other large-scale upgrades, a 2-micron laser source so Seb showed me the one that UoA are developing.
Work at other OzGrav Nodes
At UWA, I had long discussions with Zhao and gave some input on their plans to develop technologies for Voyager. The Gingin facility is potentially the only site in the next few years to have a suspended Fabry-Perot cavity with silicon optics and two micron lasers and thus could be valuable for testing.
I spent two days at ANU (overlapping with Rana Adhikari during that time). We provided input on the OzGrav proposal to build a high-frequency GW detector in Australia, and Bram and I discussed the requirements for two-stage tip-tilt.