Procedure to characterize microroughness of optical thin films: application to ion-beam-sputtered vacuum-ultraviolet coatings.

A method for characterizing the microroughness of samples in optical coating technology is developed. Measurements over different spatial-frequency ranges are composed into a single power spectral density (PSD) covering a large bandwidth. This is followed by the extraction of characteristic parameters through fitting of the PSD to a suitable combination of theoretical models. The method allows us to combine microroughness measurements performed with different techniques, and the fitting procedure can be adapted to any behavior of a combined PSD. The method has been applied to a set of ion-beam-sputtered fluoride vacuum-UV coatings with increasing number of alternative low- and high-index layers. Conclusions about roughness development and microstructural growth are drawn.

[1]  C Amra,et al.  Role of interface correlation in light scattering by a multilayer. , 1992, Applied optics.

[2]  Ekaterina V. Kostyukevich,et al.  Light scattering of thin dielectric films: self-assembled monolayers on the surface of polycrystalline gold , 1999, Correlation Optics.

[3]  Etienne Quesnel,et al.  DUV light scattering and morphology of ion beam sputtered fluoride coatings , 1999, Optical Systems Design.

[4]  A. Llebaria,et al.  Roughness spectrum and surface plasmons for surfaces of silver, copper, gold, and magnesium deposits , 1983 .

[5]  E. L. Church,et al.  The Prediction Of BRDFs From Surface Profile Measurements , 1990, Optics & Photonics.

[6]  J. P. Rahn,et al.  Relationship of the total integrated scattering from multilayer-coated optics to angle of incidence, polarization, correlation length, and roughness cross-correlation properties. , 1983, Applied optics.

[7]  J. Bennett,et al.  Relation between the angular dependence of scattering and the statistical properties of optical surfaces , 1979 .

[8]  J. P. Rahn,et al.  Light scattering from multilayer optics: comparison of theory and experiment. , 1980, Applied optics.

[9]  Etienne Quesnel,et al.  High-damage-threshold fluoride UV mirrors made by ion-beam sputtering , 1998, Laser Damage.

[10]  C. Amra,et al.  Scattering From Surfaces And Multilayer Coatings: Recent Advances For A Better Investigation Of Experiment , 1989, Other Conferences.

[11]  Salvador Bosch,et al.  Effective dielectric function of mixtures of three or more materials: a numerical procedure for computations , 1999, Optical Systems Design.

[12]  J Ferré-Borrull,et al.  Roughness and Light Scattering of Ion-Beam-Sputtered Fluoride Coatings for 193 nm. , 2000, Applied optics.

[13]  A. Duparré,et al.  Relation Between Light Scattering and Morphology of Columnar Structured Optical Thin Films , 1990 .

[14]  J. Stover.  Optical Scattering: Measurement and Analysis , 1990 .

[15]  E. Church.  Fractal surface finish. , 1988, Applied optics.

[16]  J. Bennett,et al.  Stylus profiling instrument for measuring statistical properties of smooth optical surfaces. , 1981, Applied optics.

[17]  J. Bennett,et al.  Calculation of the power spectral density from surface profile data. , 1995, Applied optics.

[18]  Uwe Stamm,et al.  Recent developments of industrial excimer laser technology , 1997, International Symposium on High Power Laser Systems and Applications.

[19]  J. Elson.  Theory of Light Scattering from a Rough Surface with an Inhomogeneous Dielectric Permittivity , 1984, Third Topical Meeting on Optical Interference Coatings.

[20]  Gunther Notni,et al.  Multitype surface and thin film characterization using light scattering, scanning force microscopy, and white light interferometry , 1999, Optics + Photonics.

[21]  Etienne Quesnel,et al.  Near-UV to IR optical characterization of YF3 thin films deposited by evaporation and ion beam processes , 1996, Optical Systems Design.

[22]  P. Hall.  Introduction to Surface Roughness and Scattering , 1989 .

[23]  H Truckenbrodt,et al.  Interfacial roughness and related scatter in ultraviolet optical coatings: a systematic experimental approach. , 1998, Applied optics.

[24]  D. Rönnow.  Elastic light scattering by thin films : spectroscopic measurements and analysis , 1996 .