An apparatus to record scattered light in whole space over a large range of visible and infrared wavelengths (0.45-10.6 µm) is described. Parasitic light, calibration, and dynamic range are discussed to point out performances and limits of the experimental setup. Angular measurements at several wavelengths give access to bidimensional roughness spectra of polished samples in different frequency bandwidths. The results show overlap of the spectra at the intersection of the bandwidths, which provides an extended view of surface microroughness. In the midinfrared, measurements are more difficult, and specific problems such as thermal emission are analyzed.

Light scattering and Atomic Force Microscopy are used together to analyse swface roughness in a very wide frequency bandwidth, extending from macroscopic (optical) to microscopic (AFM) scales. The two techniques are shown to be in large agreement since the roughness spectra overlap at intersection of bandwidths. A particuliar behavior of roughness is emphasized that pernits to predict scattering at very short wavelengths. Thin film materials obtained by dzfferent techniques (lAD, Ion Plating, EB) are also investigated via a comparison of roughness spectra measured before and after coating in all bandwidths. 614 ISPIE Vol. 2253 O-8194-1562-6/94/$6.OO Downloaded From: http://proceedings.spiedigitallibrary.org/ on 10/08/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx SPIE Vol. 2253 / 615 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 10/08/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

We present Laser Induced Damage Threshold (LIDT) results on multilayer components with different optical functions for near infrared applications. In this paper, we investigate the different fabrication steps of such functions. In particular, we show experimental results on surface preparation (polishing, cleaning,) and on deposition techniques (Ion beam assisted process) related to the materials involved in coatings. Laser damage tests are performed at 1064-nm with a 5-ns pulse Nd:Yag laser and experiments are made at surfaces of optical components using a 12 µm diameter focused beam. Accurate damage probability curves are plotted thanks to a reliable statistical measurement of laser damage. Use of a statistical model permits to deduce the densities of laser damage precursors. A systematic analysis of all the steps involved in fabrication allows then to build multilayer components with high laser induced damage resistance.

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