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Optical Glass Properties

Densely Packed Thin Film Dielectric Coatings

Multi-layer dielectric coatings are constructed from thin layers of materials such as Magnesium Fluoride and Calcium Fluoride and metal oxides which are deposited onto an optical substrate. The combination of variables including material composition, thickness and number of layers will determine the reflectivity and transmitivity of the coating. Custom design of these optical coatings can produce almost any desired characteristic.

The process used for custom thin-film dielectric coating deposition depends on the exact application and specifics on thickness, density and index of refraction. If it is desirable to have a higher packing density, such as for passivation films, Ion Assisted Deposition (IAD) can be utilized. IAD films are more robust, more scratch resistant less stressed, and so are more durable and moisture resistant. If the films are as dense as the substrate, the resulting match of the refractive indices will also improve the optical performance.

Oxides deposited include:

  • Aluminum Oxide (Al203)
  • Silicon Dioxide (SiO2)
  • Magnesium Oxide
  • Titanium Dioxide (T2O2)
  • Iron Oxide
  • Niobium Oxide
  • Tantalum Oxide
  • Tungsten Oxide
  • Zirconium Oxide
  • Ruthenium Oxide

Valley also offers coatings produced by other physical vapor deposition processes including thermal evaporation, electron beam deposition and sputtering. The capability to co-deposit 2 materials simultaneously also enables the creation of exotic alloys and the ability to further customize multi-layer coatings.

Return to Home Page: Custom optical thin film coatings available from Valley Design