eXtreme Low Optical Scattering Mirrors – X-LOSM

The X-LOSM project aims to produce a new generation of Bragg dielectric mirrors with extremely low optical losses to be used in Fabry-Perot cavities for frontier optical experiments. Thanks to outstanding polishing capability, the main source of optical losses in the mirrors is now the point defects found in the layers of the high reflective coating. The ambitious goal of X-LOSM is to reduce the size and the density of these point-like defects in order to decrease by two the coating scattering loss. That would allow unprecedented measurement sensitivity for experiments relying on very low loss optical resonators.
X-LOSM is based on an interdisciplinary approach involving thin-film fabrication process, optical characterization in order assess the point-like defects in term of density/size/optical scattering, microstructural analysis in order to understand their composition and optical modelization to forecast and optimize the final performances of the reflective coating.
The X-LOSM will gather four French laboratories of excellence with complementary expertises in coating production (LMA, IP2I), structural analysis (MATEIS, INSA), scattering measurement and simulations (CONCEPT, Institut Fresnel) and very high finesse optical cavity (BMV, LNCMI).