• 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.

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.

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

Zerodur optical flat with hole.