This is an overview of the adaptive optics used in Advanced LIGO (aLIGO), known as the thermal compensation system (TCS). The thermal compensation system was designed to minimize thermally-induced spatial distortions in the interferometer optical modes and to provide some correction for static curvature errors in the core optics of aLIGO. The TCS is comprised of ring heater actuators, spatially tunable CO2 laser projectors and Hartmann wavefront sensors. The system meets the requirements of correcting for nominal distortion in Advanced LIGO to a maximum residual error of 5.4nm, weighted across the laser beam, for up to 125W of laser input power into the interferometer.
@article{arxiv.1608.02934,
title = {Overview of Advanced LIGO Adaptive Optics},
author = {Aidan F. Brooks and Benjamin Abbott and Muzammil A. Arain and Giacomo Ciani and Ayodele Cole and Greg Grabeel and Eric Gustafson and Chris Guido and Matthew Heintze and Alastair Heptonstall and Mindy Jacobson and Won Kim and Eleanor King and Alexander Lynch and Stephen O'Connor and David Ottaway and Ken Mailand and Guido Mueller and Jesper Munch and Virginio Sannibale and Zhenhua Shao and Michael Smith and Peter Veitch and Thomas Vo and Cheryl Vorvick and Phil Willems},
journal= {arXiv preprint arXiv:1608.02934},
year = {2016}
}