Coating designs and coating characteristics in vacuum and air
Because on-line characterization is done in vacuum while manufactured coating is used in different environment (referred to as air) one should always distinguish between coating design and coating characteristics in vacuum and air. In situ measurements and the on-line characterization procedure provide information about actual coating spectral characteristics and actual coating design in vacuum. On-line re-optimization is done for the coating design in air and with respect to air target spectral characteristics. It is possible that the type of these characteristics as well as their spectral range and incidence angle are different from those used for monitoring purposes.
The correspondence between coating designs and coating characteristics in vacuum and air is established basing on layer material indices in vacuum and air and material correction factors setting the ratios of air and vacuum layer thicknesses.
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