Titania-doped tantala/silica coatings for gravitational-wave detection

Abstract

Reducing thermal noise from optical coatings is crucial to reaching the required sensitivity in next generation interferometric gravitational-waves detectors. Here we show that adding TiO${}_2$ to Ta${}_2$O${}_5$ in Ta${}_2$O${}_5$/SiO${}_2$ coatings reduces the internal friction and in addition present data confirming it reduces thermal noise. We also show that TiO${}_2$-doped Ta${}_2$O${}_5$/SiO${}_2$ coatings are close to satisfying the optical absorption requirements of second generation gravitational-wave detectors.