An instrument for total backscattering and forward-scattering measurements of optical coating components at 157 and 193 nm is described. The system is operated in both vacuum and nitrogen purge gas. An excimer laser as well as a deuterium lamp can be used as a radiation source. Suppression of the background signal level to 1 part in 10<sup>6</sup> permits measurements even of low-scatter samples such as superpolished substrates and antireflection coatings. Results of investigations of antireflective and highly reflective multilayers and CaF<sub>2</sub> substrates reveal scattering from surface and interface roughness as well as from the volume of the substrate material. First steps to extend the instrument for angle-resolved scatter, transmittance, and reflectance measurements are described.
© 2002 Optical Society of America
(120.5820) Instrumentation, measurement, and metrology : Scattering measurements
(240.5770) Optics at surfaces : Roughness
(260.7190) Physical optics : Ultraviolet
(310.0310) Thin films : Thin films
(310.1620) Thin films : Interference coatings
Stefan Gliech, Jörg Steinert, and Angela Duparré, "Light-Scattering Measurements of Optical Thin-Film Components at 157 and 193 nm," Appl. Opt. 41, 3224-3235 (2002)