This premium fused silica wafer is manufactured from Corning 7980 Grade 0F, offering excellent optical quality, flatness, and durability. It measures 200.00 mm ± 0.20 mm in diameter and 1.00 mm ± 0.10 mm in thickness. With a clear aperture of ≈ 85%, it provides a large usable area while maintaining strict optical tolerances. Surface cosmetics are held to 40/20 scratch-dig, reflective wavefront error is under 1 wave per inch, and transmitted wavefront error is below 0.25 waves per inch (at the 632 nm metrology wavelength). Parallelism is kept under 30 seconds of arc. Edges are fine-edge ground with a safety bevel, and defect control ensures chips under 0.5 mm. Surface roughness is better than 1 nm RMS and total thickness variation (TTV) is under 5 µm.