Optical Flat

Optical Systems Division Optical Components Group Electro-Optics Group Markets & Applications Case Studies Contact

Optical Components Group Aspheres Extreme Precision Optics Super Finishing Optical Windows High Fluence Products Transmission Spheres & Flats Precision Reference Surfaces Optical Mirrors High Precision Prisms Spherical Optics Thin Plate Optics Glass & Ceramic Machining Semiconductor Stage Components Coatings Optical Flats

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 Flats
Please use this form to tell us about the optical flats you need, or ask questions about any of Zygo's optical products, services, or capabilities. You may send any additional information, including specifications and/or prints, to:

First Name * Last Name *
Title * E-mail Address *
Company or Organization * Phone Number *
Street Address * City *
State/Province* Zip/Postal Code *
Country *
If you experience any difficulty submitting this form, please contact:
Optic Type:     
Optic Shape:     
Coating Type:
Additional Info: 
* Required entries  

AMETEK, Inc. Logo

Contact ZYGO Optical Systems Division at 800-ZYGO-NOW.