Fused Quartz Optical Flats

Pricing Charts for Stock Optical Flats

Single Surface, Round: One surface of the glass is polished to flatness indicated in table. Other surface has "commercial polish" which means it is clear but flatness is unspecified.
Size Round Lambda/20 0.0000012 inches  1.2 micro inches  ($US) Lambda/10 0.0000025 inches 2.5 micro inches ($US) Lambda/4 0.0000062 inches 6.2 micro inches ($US) Thickness
1" 143 130 110 0.5"
2" 225 180 170 0.625"
3" 390 379 300 0.688"
4" 575 525 438 0.75"
5" 900 695 650 0.875"
6" 1200 990 830 1"
8" 3075 2520 1995 1.313"
10" 4090 3700 3475 1.688"
12" 6800 5900 5400 2"


Double Surface, Round: Both surfaces of glass are polished to flatness indicated in table.
Size Round Lambda/20 0.0000012 inches 1.2 micro inches ($US) Lambda/10 0.0000025 inches 2.5 micro inches ($US) Lambda/4 0.0000062 inches 6.2 micro inches ($US) Thickness
1" 225 170 160 0.5"
2" 280 210 200 0.625"
3" 565 465 385 0.688"
4" 825 650 590 0.75"
5" 1170 950 795 0.875"
6" 1700 1450 1200 1"
8" 3700 3000 2600 1.313"
10" 5600 5100 4800 1.688"
12" 7950 7000 6500 2"

Most items are ready to ship within one week after receipt of order. Other sizes and shapes can be made. Call or e-mail us to request a quote.

Common Specifications:
  • Material: Fused silica or fused quartz.
  • Tolerance of diameter and thickness: +/- 0.060 inches.
  • Typical surface roughness is 5 Angstroms RMS.
  • Flatness values are Peak-to-Valley where Lambda=633 nm.
  • Measurements are NIST certified.
  • Parallelism is typically 4 arc minutes or better, but it is not guaranteed.
  • Scratch-dig is typically 80-50, but it is not guaranteed.
  • Parallelism up to 1 arc second and scratch-dig to 10-5 and 5-0 are available. Contact us to request a quote.
  • Each optic is packed in its own storage case.
  • *Optional Coating: Contrast-enhancing TiO coating is available for the single-sided flats.  If you would use an optical flat in contact testing and the part to be tested has a flat or matte finish, this coating may enhance the contrast of the interference fringe pattern, which would make the fringes easier to see.  This coating does not make the surface more resistant to scratches.


Optical Flats as Windows:    

The prices in the tables above are for optical reference flats that are designed to be used in surface contact testing, or as front surface mirrors if appropriately coated. They are not designed to be used as high-precision windows, where you are using the light that transmits through the optic, not just reflects off one surface of it. Although they may work well as windows for some applications, parameters affecting their use as windows such as parallelism, internal defects and striae, and transmitted wavefront accuracy are generally of good quality, but they are not held to any specific value. If you are looking for high-precision windows where you need to hold the transmitted wavefront accuracy to a specific value, call or e-mail for a quote.


Resurfacing and Calibration:

We can re-surface your flats to your specifications. Please call or e-mail for a quote.

Some unique optical flats fabricated over the years:


One inch diameter flats in a custom wood case.

One inch diameter optical flats in a custom wood case.


Fused silica optical flat, 18" x2", lambda/15 peak-to-valley.

Fused silica optical flat, 18"x2", lambda/15 peak-to-valley.


Custom 10"x10" fused silica optical flat

10"x10" square optical flat, 1.5 inches thick.


Optical flat in the shape of a ring for measuring the figure of a flat surface that has a protruding shaft in the middle of it.


Optical Flat with a thru-hole.

Optical flat with a thru-hole.

9.5" x 2" rectangular optical flat made from fused silica.

Rectangular optical flat with a gold coating.

A 3 inch dia. flat with a 2.5 inch thru-hole.

Zerodur optical flat with hole.


13 inch diameter, lambda/4, optical flats.
Aluminum-coated mirror with thru-hole that has counter-bore. This hole makes a 45 degree angle with the surface. The diameter of the hole changes in the middle of the substrate. The aluminum-coated surface is facing down. Custom lambda/4 mirror substrates, 13 inches diameter, 1-inch thick.


Optical flat with blind hole.  This hole has one opening to the back surface. The flat surface is unbroken. 

Optical flat with a very thin wall, high flatness and parallelism.


Optical flat with a groove and an acute angle. 

Optical flat with rounded corners.


Optical flat with a groove and a beveled edge.

A variety of reference flats with gold coating.


Fused Silica Window with beveled edge.

Large Square flat in an optional Pelican case.


Please check out our Optics Cleaning Kit.

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Custom Scientific, Inc.
3852 North 15th Avenue
Phoenix, Arizona 85015 USA
Phone: 602-200-9200
Fax: 602-200-9206

Last modified June 11th, 2015.