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Applied Optics

Applied Optics


  • Editor: James C. Wyant
  • Vol. 46, Iss. 16 — Jun. 1, 2007
  • pp: 3221–3226

Nanoporous structure of a GdF3 thin film evaluated by variable angle spectroscopic ellipsometry

Jue Wang, Robert Maier, Paul G. Dewa, Horst Schreiber, Robert A. Bellman, and David Dawson Elli  »View Author Affiliations

Applied Optics, Vol. 46, Issue 16, pp. 3221-3226 (2007)

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As excimer lasers extend to deep-ultraviolet and vacuum-ultraviolet wavelengths at 193 and 157 nm , optical coatings experience the challenge of eliminating possible environmental contamination, reducing scattering loss, and increasing laser irradiation durability. Wide bandgap metal fluorides become the materials of choice for the laser optics applications. To understand the optical properties of nanostructure fluoride films, thin G d F 3 films grown on CaF 2 (111) substrates were evaluated by variable angle spectroscopic ellipsometry. An effective medium approximation model was used to determine both the film porosity and the surface roughness. Structural evolution of the G d F 3 film was revealed with improved ellipsometric modeling, suggesting the existence of multilayer structure, a densified bottom layer, middle layers with increasing porosity, and a rough surface. The nanostructure of the film and the surface roughness were confirmed by atomic force microscopy. The attraction of the nanostructure to environmental contamination was experimentally demonstrated.

© 2007 Optical Society of America

OCIS Codes
(160.4670) Materials : Optical materials
(310.0310) Thin films : Thin films

ToC Category:
Thin Films

Original Manuscript: August 7, 2006
Revised Manuscript: December 4, 2006
Manuscript Accepted: January 30, 2007
Published: May 15, 2007

Jue Wang, Robert Maier, Paul G. Dewa, Horst Schreiber, Robert A. Bellman, and David Dawson Elli, "Nanoporous structure of a GdF3 thin film evaluated by variable angle spectroscopic ellipsometry," Appl. Opt. 46, 3221-3226 (2007)

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