Research On The Technolohy Of Measuring Laser Gyro

The ultra-low loss mirror is one of the key elements affecting laser gyro performance. It is required to machining mirrors with super-smooth surface to obtain low loss of the mirror. The technology of measuring and evaluating the super-smooth surface becomes more and more important.The quality measurement about the super-smooth surface of mirrors mainly includes:the surface profile measurement; the surface defects detection and the subsurface damage detection. In this paper, the mirrors surface profile measurement is mainly studied.The main work includes:1. The study on the microscopic morphology measurement of the mirror surface includes:the relationship of the evaluating parameters (such as RMS PSD waveness) between the wavelength and the surface microscopic morphology, the applicability of the surface roughness evaluation (RMS PSD) and the analysis of the microscopic morphology properties producted by different manufacturing techniques.2. The surface profile measurement of mirrors and the curvature radius measurement are also studied in this paper. Based on the study of the microscopic morphology properties, the surface profile properties are analyzed. The main reason which causes the difference of the curvature radiuses before and after measurement is discussed.Based on the study of lots of super-smooth surface properties measurements, it draws a conclusion as follows:①The wavelength used in the measurement should be divided by the surface profile, waveness and roughness of different mirrors;②In the surface roughness measurement, the Optical Profiler should be used in the microscopic morphology measurement of intermediate frequency, and the Atomic force microscope should be used in the microscopic morphology measurement of high frequency;③In the surface roughness evaluation, the evaluation combining the RMS and the PSD plot is adopted. The PSD plot guides the improvement of the surface manufacturing technique. The surface quality evaluation by the RMS controls the surface quality;④The surface waveness is the ultimate reason that causes the indeterminacy phenomenon in the curvature radius measurement;⑤Based on the analysis and the manufacturing technique, the classification of mirrors according to measurements is established.