Multi-Material Coatings with Reduced Thermal Noise

Understand

The most sensitive measurements of time and space are made with resonant optical cavities, and these measurements are limited by coating thermal noise.

• The mechanical and optical performance requirements placed on coating materials, especially for interferometric gravitational wave detectors, have proven extremely difficult to meet despite a lengthy search.
• In this paper we propose a new approach to high performance coatings; the use of multiple materials at different depths in the coating.
• To support this we generalize previous work on thermal noise in two-material coatings to an arbitrary multi-material stack, and develop a means of estimating absorption in these multi- material coatings.