Thermal noise from optical coatings in gravitational wave detectors.

Thermo-optic noise in coated mirrors for high-precision optical measurements

Thermal fluctuations in the coatings used to make high reflectors are becoming significant noise sources in precision optical measurements and are particularly relevant to advanced gravitational-wave detectors. There are two recognized sources of coating thermal noise; mechanical loss and thermal dissipation. Thermal dissipation causes thermal fluctuations in the coating which produce noise via...

Direct Measurements of Spatial Homogeneity of Coating Mirrors Thermal Noise and non Periodic Coatings for Interferometric Gravitational Wave Detectors

Development of Mirror Coatings for Gravitational Wave Detectors

The first detections of gravitational waves, GW150914 and GW151226, were associated with the coalescence of stellar mass black holes, heralding the opening of an entirely new way to observe the Universe. Many decades of development were invested to achieve the sensitivities required to observe gravitational waves, with peak strains associated with GW150914 at the level of 10−21. Gravitational w...

Excess mechanical loss associated with dielectric mirror coatings on test masses in interferometric gravitational wave detectors

Interferometric gravitational wave detectors use mirrors whose substrates are formed from materials of low intrinsic mechanical dissipation. The two most likely choices for the test masses in future advanced detectors are fused silica or sapphire (Rowan S et a1 2000 Plzys. Lett. A 265 5). These test masses must be coated to form minors, highly reflecting at 1064 nm. We have measured the excess ...

Effect of Stress and Temperature on the Optical Properties of Silicon Nitride Membranes at 1,550 nm

Future gravitational-wave detectors operated at cryogenic temperatures are expected to be limited by thermal noise of the highly reflective mirror coatings. Silicon nitride is an interesting material for such coatings as it shows very low mechanical loss, a property related to low thermal noise, which is known to further decrease under stress. Low optical absorption is also required to maintain...