ITAR registered and ROHS & REACH compliant

ISO 9001:2015 certification
View or download:

ANAB and RvA

Mounted Reference Flats

Precision Optical exclusively manufactures its own in-house reference flats which are necessary for interferometric inspection.  We now offer these exceptional high quality reference optics to our customers.

Our transmission flats (TF’s) are made from high performance fused silica and can be AR coated on the rear surface to act as 4% return (standard) TF’s.  We can offer any available AR coating within the range of our coating capability.  We can also offer attenuated transmission flats variants (ATF’s).  Return flats (RF’s) can be made out of either fused silica or glass ceramic and can be supplied uncoated or with metallic coating for increased reflectance.

For mounted reference flats (TF or RF), we currently offer 101.6mm (4 inch), 152.4mm (6 inch) and 304.8 (12 inch) clear aperture options.  We offer flatness options ranging from lambda/15 PV (or PVr) to lambda/60 PV (or PVr), size dependent.

Our mounting cells are adaptable to industry standard bayonets and are a fantastic addition to high resolution laser interferometers when peak performance is essential.  The mounted reference flat will be provided securely within a pelican case with custom foam inserts for safe transit, storage and reuse.

Accompanying data package includes detailed interferometric screenshot displaying mean, range and standard deviation along with a CofC that lists environmental conditions at time of test, test instrument, reference standard and NIST traceable test number for our test instrument calibration (reference flat is not calibrated, it is certified).  The average raw dataset can be supplied in the following formats:  4D (.h5), Wyko/Veeco (.opd), Opticode (.map), MetroPro (.dat), CODE V (.int) or ESD, HDF4 (.HDF).

We have a simple part numbering system for defining and ordering your mounted reference flat preferences.  Please contact us and our sales team will efficiently get you the quote you need!


Get a Quote for Mounted Reference Flats

Typical Specifications

  • Material: Fused Silica, Zerodur
  • Clear Aperture Sizes: 101.6mm,152.4mm, 304.8mm
  • Clear Aperture Types: Circular
  • Surface Quality: 20/10 Per MIL-PRF-13830_B
  • Surface Flatness: λ/60, λ/50, λ/40, λ/20, λ/15 or custom
  • Edge Chamfers: 1.0mm – 2.0mm face width
  • Wedge Angle: 10-30 arc minutes
  • Coatings: Laser line anti-reflection, attenuating, protected metal mirrors
  • Mounting Cell: Anodized and adaptable to industry-standard bayonets
  • Packaging: Pet-G and/or Pelican


Donald A. Pearson II

Äpre Instruments

I am always very happy with Precision Optical. Their lead times and delivered product are excellent. I wish more of our suppliers were like Precision Optical!

Brian Monacelli, Ph.D.

Laser Technology Professor - Pasadena City College

Partnering with Precision Optical through their Ensign-Lambert Optics Education Program has allowed over 120 of my laser and optical technology students to gain real-world perspective with hands-on work in optics. These interactions directly motivate the next generation of technicians as they learn first-hand how this fascinating work with industrial hardware will translate into rewarding careers.