| 摘要 |
PURPOSE:To provide low thermal expansibility to a mirror for a laser device and to make the mirror fit for high output by coating the ceramic substrate of the mirror with a material having high reflectance. CONSTITUTION:The specular surface of a blank of 122mm. diameter and 22mm. thickness obtd. by sintering SiC contg. 2% BeO at 2,050 deg.C for 1hr in vacuum while applying 300kg/mm.<2> pressure is polished to <=100Angstrom surface roughness, and the resulting substrate 1 is coated with Au as a metal 2 having oxidation resistance and high reflectance to obtain a mirror reflecting 98.5% of CO2 laser light of 10.6mum wavelength. The mirror has heat conductivity close to that of Cu, the temp. is hardly raised by forming a water-cooled structure, and the substrate has a remarkably low coefft. of thermal expansion, so even when the mirror is used in high-output operation over a long time, the mirror undergoes a very little deformation, and it increase the output and prolongs the life. |
