Single-sided Optical Flats for Precision Measurement, Balzers, EIS Optics, Oerlikon Optics, Unaxis

An Ocean Thin Films Optical Flat is a finely polished flat surface used as a reference against which the flatness of a test surface may be compared. We offer single-sided optical flats in either fused silica or Zerodur™. Additionally, the flats can be enhanced with an aluminum coating to increase contrast and improve the visual reference. Starting at $200, our 32 different flats range in size from 1" to 6" in diameter and are available in 1/20 wave, 1/10 wave or 1/4 wave flatness accuracies.







Features:
• Easy-to-use
• Provides immediate results
• Available in 1/20l, 1/10l or 1/4l accuracies
• Optional aluminum coating increased contrast

Ocean Thin Films Flats can be used to visually inspect optical components such as mirrors, filters, prisms and windows. 

When an Ocean Thin Films Flat is placed in contact with a test surface and viewed with a monochromatic light, an interference pattern of light and dark bands is formed. The shape of this interference pattern provides an accurate visual representation of the flatness of the test surface. A curved interference pattern indicates that the flatness of the test surface is less than that of the reference surface. Evenly spaced interference patterns indicate that the test surface is equal to or higher than that of the reference surface.

Flatness Error of One Fringe (1/2l) (top view of optical flat)

Test Piece Flat (top view of optical flat)

Based on the application requirements, users can choose between 1/20l, 1/10l and 1/4l accuracies. For instance, if the test surface is flatter than 1/4l , then a more precise 1/10l flat is required to display a change in the interference pattern.

Users can also choose between flats made of fused silica or Zerodur. Fused silica has a low thermal expansion of 0.55 x 10-6 per ºC and is highly resistant to abrasions. Zerodur is a yellow-tinted clear glass ceramic that exhibits a low thermal expansion of  0.10 x 10-6 per ºC.
Optical flats can lose their degree of precision with repeated use. Ocean Optics can recalibrate and repolish your Ocean Optics Optical Flat for a small fee. Please contact an Applications Scientist for more information on this service.