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

TL;DR

This paper demonstrates that doping tantala/silica coatings with TiO₂ reduces thermal noise and internal friction, making them promising for improving the sensitivity of next-generation gravitational-wave detectors.

Contribution

It introduces TiO₂ doping in tantala/silica coatings and provides experimental evidence of reduced thermal noise and acceptable optical absorption for gravitational-wave detection.

Findings

TiO₂ doping reduces internal friction in coatings

Doped coatings show lower thermal noise levels

Optical absorption remains within acceptable limits

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.