1 August 1990 Scattering from optical surfaces and coatings: an easy investigation of microroughness
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Proceedings Volume 1270, Optical Thin Films and Applications; (1990) https://doi.org/10.1117/12.20366
Event: The International Congress on Optical Science and Engineering, 1990, The Hague, Netherlands
Abstract
We show how the anisotropy of scattering enables to point out the origin of microroughness in optical coatings with no ambiguity. Experimental results prove that residual roughness due to material microstructure is negligible with coatings produced by Ion Assisted or Ion Plating deposition. In these conditions, and provided that the substrate is measured before coating, prediction of scattering from a stack of any design requires the knowledge of only two cut-off frequencies that describe the action of materials at interfaces. These parameters can be determined with single layers and then can be used for more complex optical systems. Since isotropy degree variation of scattering does not depend on the design of the coating, it enables to show that the differences that can occur between calculation and measurements are due to thickness or index errors on the layers. Therefore the substrate roughness plays a primordial role and we compare, using numerical calculation, the roughness spectra that can be obtained with mechanical or optical measurements.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Claude Amra, Didier Torricini, Yannick Boucher, Laurent Bruel, Emile P. Pelletier, "Scattering from optical surfaces and coatings: an easy investigation of microroughness", Proc. SPIE 1270, Optical Thin Films and Applications, (1 August 1990); doi: 10.1117/12.20366; https://doi.org/10.1117/12.20366
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