Optical Flat

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Optical Flats Custom Fabricated Single- or Double-Sided Optical Flats

Large Optical Flats, Optical Flat Polishing Machine
Large Optical Flats, Optical Flat Polishing Machine
The term Optical Flat can mean different things to different people. A single-sided optical flat, so called because only one side is ground and polished to specification, is most often used as a reference surface to determine the flatness quality of another flat optical surface, such as the face of a prism, optical mirror, optical window, or another optical flat. When the optical flat is placed in contact with the test surface and illuminated with a monochromatic light source, an interference pattern is visible, the shape and character of which indicates the flatness of the test surface. A single-sided optical flat may also serve as the substrate for a high-quality optical mirror.

A double-sided optical flat, where both sides are polished to specification, may also be used as a reference surface for evaluating a test optic, or it may be used as a optical window, or as oil-on plates for material qualification, such as optical homogeneity.

For windows, the material should be chosen carefully to suit the application. Zygo can fabricate custom optical flats from a wide range of materials, including, but not limited to:

Cleartran (water-clear Zinc Sulfide - ZnS)


Glass (fused silica, BK7, etc.)

Sapphire (various crystal orientations)


Zinc selenide (ZnSe)


Zygo can fabricate optical flats ranging in size from a few millimeters to greater than 1 meter.


Zygo has developed a wide range of manufacturing processes to fabricate optical flats and windows that operate in the infrared (IR), visible, and ultra-violet (UV) parts of the spectrum. Similarly, Zygo has experience with multi-spectral applications, combining IR and visible. Optical flats can be provided with or without thin film coatings.


Zygo has a long tradition of manufacturing custom-made optical flats for a wide variety of applications, including, but not limited to:

• Amplifier Slabs, discs and rods

• Debris Shields

• Infrared (IR) windows

• Intelligence, surveillance & reconnaissance (ISR applications)

Laser fusion optics

Reference surfaces

• Ultra-violet (UV) windows

• Visible windows

Inquiry/Quote Form – Optical Flat
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Contact ZYGO Optical Systems Division at 800-ZYGO-NOW.