Mechanical loss in state-of-the-art amorphous optical coatings

Massimo Granata (1) , Emeline Saracco (1) , Nazario Morgado (1) , Alix Cajgfinger (1) , Gianpietro Cagnoli (1, 2) , Jérôme Degallaix (1) , Vincent Dolique (1) , Danièle Forest (1) , Janyce Franc (1) , Christophe Michel (1) , Laurent Pinard (1) , Raffaele Flaminio (3)

1 LMA - Laboratoire des matériaux avancés
2 ILM - Institut Lumière Matière [Villeurbanne]
3 NAOJ - National Astronomical Observatory of Japan

We present the results of mechanical characterizations of many different high-quality optical coatings made of ion-beam-sputtered titania-doped tantala and silica, developed originally for interferometric gravitational-wave detectors. Our data show that in multilayer stacks (like high-reflection Bragg mirrors, for example) the measured coating dissipation is systematically higher than the expectation and is correlated with the stress condition in the sample. This has a particular relevance for the noise budget of current advanced gravitational-wave interferometers, and, more generally, for any experiment involving thermal-noise-limited optical cavities.

Domaines: Optique [physics.optics]; Science des matériaux [cond-mat.mtrl-sci]

Massimo Granata, Emeline Saracco, Nazario Morgado, Alix Cajgfinger, Gianpietro Cagnoli, et al.. Mechanical loss in state-of-the-art amorphous optical coatings. Physical Review D, 2016, 93, ⟨10.1103/PhysRevD.93.012007⟩. ⟨in2p3-01357284⟩