Paper
2 July 1998 Polarizing interference coatings made with anisotropic thin films
Francois Flory, Celine Defay
Author Affiliations +
Proceedings Volume 3405, ROMOPTO '97: Fifth Conference on Optics; (1998) https://doi.org/10.1117/12.312722
Event: ROMOPTO '97: Fifth Conference on Optics, 1997, Bucharest, Romania
Abstract
It is now well known that the microstructure of materials in thin film form can be slightly different from that of corresponding bulk materials. Conventional evaporation using a heated crucible or an electron beam gun generally leads to a lacunar structure in columns. Some consequences of this microstructure on the optical properties of the films are well-known. The refractive indices are slightly smaller than that of the bulk material; water adsorption-desorption in the voids leads to variations of the spectral reflection and transmission of the coatings. But apart from these disadvantages, the columnar structure can present advantages because it also induces anisotropy of refractive index. When deposited with an ion beam assistance the microstructure of the material is modify and so is its anisotropy. The anisotropy can then be controlled through the ion energy, making it possible to construct multilayer filters combining both isotropic films and anisotropic films. This opens the way for the making of components acting on the polarization state of light. Results of calculation for different components are presented. Planar non absorbing monochromatic polarizers or polarization rotators can be made in this way. The difficulty in controlling the deposition comes from the fact that the anisotropic layers must be deposited on non rotating substrates. This problem is discussed and examples of measured optical properties of multilayer filters will be given.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Francois Flory and Celine Defay "Polarizing interference coatings made with anisotropic thin films", Proc. SPIE 3405, ROMOPTO '97: Fifth Conference on Optics, (2 July 1998); https://doi.org/10.1117/12.312722
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KEYWORDS
Ions

Polarization

Thin films

Anisotropy

Refractive index

Polarizers

Radio propagation

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