Construction of a large-scale cryogenic gravitational-wave telescope KAGRA has been completed and the four sapphire test masses have been installed in cryostat vacuum chambers. It recently turned out that a sapphire substrate used for one of the input test masses shows a characteristic strcuture in its transmission map due to non-uniformity of the crystal. We performed an interferometer simulation to see the influence of the non-uniformity using measured transmission/reflection maps.
@article{arxiv.1907.12785,
title = {Influence of non-uniformity in sapphire substrates for a gravitational wave telescope},
author = {Kentaro Somiya and Eiichi Hirose and Yuta Michimura},
journal= {arXiv preprint arXiv:1907.12785},
year = {2020}
}