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Double sided flat may be used as a reference (test plate) against which the flatness of an unknown surface can be compared or as an optical window. Advanced Optics offers double sided optical flats made of low expansion borosilicate glass, fused quartz, fused silica and ZERODUR® up to 8 inches in diameter to meet various demanding applications. Surface flatness of λ/4 and λ/10 are available in low expansion borosilicate glass and λ/4, λ/10 and λ/20 in fused quartz, fused silica and ZERODUR®.

In addition to our in-stock optical flats, we also offer custom fabricated optical flats to meet exact customer requirements.

Optical Flat Specifications:

Many of our optical flats are manufactured out of synthetic fused silica, which provides superior transmission characteristics, a high degree of purity, exceptional environmental durability, and a low coefficient of thermal expansion. Due to these attributes, our double sided optical flats can be used as an optical window.

The accuracy of each optical flat is traceable to the National Institute of Standards and Technology.

View our in-stock double sided optical flats below:

Surface Accuracy: Double Sided Diameter Fused Silica (Thickness)
λ/20 (0.000001") 25.4 (1") 12.7 (1/2")
λ/10 (0.000002") 25.4 (1") 12.7 (1/2")
λ/20 (0.000001") 50.8 (2") 15.9 (5/8")
λ/10 (0.000002") 50.8 (2") 15.9 (5/8")
λ/20 (0.000001") 76.2 (3") 15.9 (5/8")
λ/10 wave (0.000002") 76.2 (3") 15.9 (5/8")
λ/20 wave (0.000001") 101.6 (4") 19.1 (3/4")
λ/10 wave (0.000002") 101.6 (4") 19.1 (3/4")
λ/20 (0.000001") 127 (5") 19.1 (3/4")
λ/10 (0.000002") 127 (5") 19.1 (3/4")
λ/20 (0.000001") 152.4 (6") 25.4 (1")
λ/10 (0.000002") 152.4 (6") 25.4 (1")
λ/20 (0.000001") 203.2 (8") 33.8 (1.33")
λ/10 (0.000002") 203.2 (8") 33.8 (1.33")

Fused Silica Technical Data Sheet from Corning Incorporated Fused Silica Technical Data Sheet from Corning Incorporated (pdf)

Advanced Optics offers optical flat resurfacing for double sided flats. Optical flats and windows become worn and abraded in use and accuracy is lost. This degradation in performance is due to a decrease in the distinctness of the interference pattern, and to a change in figure caused by scratches. Repolishing the surface of the optical flat back to its original accuracy can be less costly than replacement. Advanced Optics maintains an optical flat refinishing service with fast turnaround time.

Flatness Error of One Fringe
(1/2 wave)
(top view of optical flat)
Test Piece Perfectly Flat
(top view of optical flat)

Have a question? Give us call and tell us about your project. (262) 548-1155