Crystalline oxides for mirror coatings

Jean-Pierre LOCQUET
Dept. of Physics and Astronomy, KU Leuven, Leuven, Belgium

Reflective coatings on mirror bodies are key elements of gravitational wave detectors and are a topic of intense research in the community. Two classes of coatings are currently studied namely a broad range of amorphous compounds and a few crystalline materials. The latter group consists  of AlGaAs / GaAs and AlGaP / GaP.
In this presentation, the potential of crystalline oxides coatings is explored. Considering the many crystalline oxide substrates that are commercially available in high quality grade, it is a clear that several of these can be used to build up optically reflective heterostructures.
A first selection is proposed based on a number of criteria that will be reviewed. These include: i) substrate considerations, ii) structural parameters, iii) solid state chemistry, iv) thermodynamics, v) elastic properties, vi) coating methodology and vii) coating tool design.