APPLICATION OF SAPPHIRE BONDING FOR INTERFEROMETRIC GRAVITATIONAL WAVE DETECTOR WITH CRYOGENIC MIRRORS

Thermal conductance and light scattering were measured for two bonded sapphire samples. A sample with adhesion free bonding (AFB) showed the same thermal conductivity as that of the bulk at cryogenic temperatures. In contrast, a finite thermal resistance was observed in the sample with hydroxide-catalysis bonding (HCB). Light scattering at λ = 488 nm from bonded region was about 10% larger than the bulk part and was about 800 ppm of an incident laser power for AFB sample.