Characterization of optical coatings using a multisource table-top scatterometer.

Light scattering measurement and analysis is a powerful tool for the characterization of optical and nonoptical surfaces. To enable a more comprehensive postmeasurement characterization, three visible laser sources were recently implemented in a highly sensitive table-top scatterometer with 3D spherical detection capability. Based on wavelength scaling, the instrument is utilized to characterize thin-film coatings and their substrates with respect to surface roughness, roughness growth, and contamination.

Scattering reduction through oblique multilayer deposition.

Scattering from multilayer coatings depends on the roughness of each interface as well as their cross-correlation properties. By depositing thin film coatings under oblique incidence, the cross-correlation properties can be specifically adapted and consequently also the scattering characteristics. This will be illustrated for Mo/Si multilayers, for which a scattering reduction of more than 30% can be achieved.

Evaluation of subsurface damage by light scattering techniques.

Subsurface damage (SSD) in optical components is almost unavoidably caused by mechanical forces involved during grinding and polishing and can be a limiting factor, in particular for applications that require high laser powers or an extreme material strength. In this paper, we report on the characterization of SSD in ground and polished optical surfaces, using different light scattering measurement techniques in the visible and extreme ultraviolet spectral ranges. The materials investigated include fused silica, borosilicate glass, and calcium fluoride.

Comprehensive nanostructure and defect analysis using a simple 3D light-scatter sensor.

Light scattering measurement and analysis is a powerful tool for the characterization of optical and nonoptical surfaces. A new 3D scatter measurement system based on a detector matrix is presented. A compact light-scatter sensor is used to characterize the scattering and nanostructures of surfaces and to identify the origins of anisotropic scattering features.

Angle-resolved scattering: an effective method for characterizing thin-film coatings.

Light scattered from interface imperfections carries valuable information about its origins. For single surfaces, light-scattering techniques have become a powerful tool for the characterization of surface roughness. For thin-film coatings, however, solving the inverse scattering problem seemed to be impossible because of the large number of parameters involved.

Angle-resolved scattering and reflectance of extreme-ultraviolet multilayer coatings: measurement and analysis.

Roughness-induced light scattering critically affects the performance of optical components, in particular at short wavelengths. We present a stand-alone instrument for angle-resolved scattering and reflectance measurements at 13.5 nm in the extreme-ultraviolet (EUV) spectral range.