Monitoring the Optical Surface Purity of Components by an Ellipsometric Method

The possibility of monitoring the chemical purity of the surface of optical components by an ellipsometric method is analyzed. The rationale for the possible measurement of the parameters of contaminating films on the optical surface of components by an ellipsometric method is examined. A simplified process for determining the thickness of a contaminating film with an extension of the feasibility of its measurement on optical components of different materials is illustrated. Ellipsometric studies of freshly polished and used metallic mirrors of copper and copper alloy (zirconium bronze), aluminum and its alloys AMG-6, AL-9, and AL-24 are carried out. Studies are also made of components composed of K-8 and K-108 (GOST 3514-94) optical glasses, the most typical materials used in manufacturing optical parts for laser technology in the visible and near IR, as well as of monocrystalline NaCl, BaF 2 , and sapphire (Al 2 O 3 ). The parameters of contaminated films on surfaces of these components are measured. It is found that the ellipsometric technique is appropropriate for use in input (prior to physical-chemical cleaning) and output (following cleaning) monitoring of optical components for evaluating the contamination of an optical surface, as well as for quantitative analysis of the concentration of contaminants on the optical surface of components in the course of completing the techniques for their physical-chemical cleaning.