Absolute Specular Reflectance Measurements of Highly Reflecting Optical Coatings at 10.6 micro.

A high precision method for measuring the specular reflectivity of mirrors at 10.6 micro with a CO(2) laser source when the reflectivity of the mirror approaches close to unity is described. The results of measurements on a range of evaporated thin film coatings are reported. Measurements at other wavelengths using a helium-neon laser have also been made, and this is discussed.