λ/4, λ/10, or λ/20 single-side or double-side optical flats.
Sydor Optics provides various optical flats, also known as “reference flats,” “test flats” or “test plates”, to meet precision tolerances for the most demanding and exacting applications. An optical flat is manufactured to be extremely flat, and used as a reference for measuring the flatness of other optics with a monochromatic light source or in interferometry applications. Some people also use word “optical flat” interchangeably with other flat optical components such as optical windows or as substrates for optical mirrors.
As with other products from Sydor Optics, optical flats are fabricated in custom sizes with different coating and beveling options, and can even be polished to include a slight wedge to reduce back reflection. Whether you need λ/4, λ/10, or λ/20 single-sided or double-sided optical flats, Sydor Optics will meet your needs for precision and accuracy.
When it comes to using optical flats for evaluating the flatness accuracy of an unknown optical surface, it’s best to choose a known vendor: Sydor Optics has decades of experience in custom fabrication and resurfacing/refinishing of optical flats.
Reference flats can be accompanied by a protective case and Sydor Optics can also provide supporting documentation and data upon request.
Available Material Types
Based upon customer demand, Sydor Optics offers Optical Flats made from the following substrate materials. Of course, if you don’t see a material you need, please contact a Sales Engineer, who will gladly discuss additional options that may be available.
- Display Glass
- Fused Quartz
- Fused SilicaPopular Materials
- Low Expansion
|Thickness Tolerance||± 0.1mm|
|Cosmetics (MIL-PRF-13830B)||60-40 to 10-5|
|Surface Roughness - before coating||≥ 3 Ǻ rms|
|Reflected Wavefront Error (RWE) - before coating||≥ 1/20 wave over clear aperture|
|Clear Aperture||≤ 95%|
|Reusable Protective Packaging||available upon request (additional fee)|
Types of Optical Flats
Single Surface Optical Flats
Single-sided optical flats are flats that are precision polished on only one side. The other side is left clear, but it is not polished to specification. The polished side of the optical flat may be used to test the flatness of other optical materials such as optical mirrors or wedge prisms. It can also be used as a substrate for optical windows.
Double Surface Optical Flats
Double-sided optical flats are flats that are precision polished to a known flatness on both sides. Because optical flats are used to test the flatness of an unknown surface, either side of a double-sided optical flat can be used for testing, or it could also be used as a substrate for a window.
Optical Flat Coating Options
- Titanium Dioxide Coating that enhances the fringes
Optical Flat Refinishing / Resurfacing
With careful usage, storage and cleaning an optical flat should provide years of use. However, accidents can happen and normal wear and tear is inevitable. Depending on the type and frequency of usage, the flatness and quality of an optical flat may diminish over time. In certain circumstances, it makes sense to refinish or resurface an optical flat to not only extend its life but also to ensure that your optical flat produces an accurate measurement every time.