Precise measurement system for reflectivity scanning of large aperture components

A precise measurement system of high reflectivity for scanning large aperture components in high power laser system is developed. The structure and working principle of this system are introduced, and those factors that influence its metrical precision are analyzed. According to theoretic analysis, precision of this measurement system is 2×10-5. Experimental measurements for capability of this system were carried out, which show that RMS of measurement in linear cavity is better than 2.052 28×10-5. Results give that the biggest measurement error is 3.554 04×10-5, which is in good agreement with the analysis. Scanning experimental measurements for large aperture components were also carried out. Results show that distribution of reflectivity is circular symmetric about the center of mirr