Optical Flats:Optical Flats are used as a reference (test plate) against which the flatness of an unknown surface may be compared.. The secondary surfaces of our single surface flats are pitch polished to window quality for viewing the interference pattern. Each flat is serialized and includes a certificate of calibration and durable storage case. Optical Flats can be supplied with both side flatness. We can supply surface flatness upto lambda/10 and Size upto 150mm . Material : Fused Silica or any specific materialOptica offers all types of windows made of different materials. Special size and materials are also available upon request. In addition, We provide various Coating on optical windows.+ Read More