Commercial Quality Windows, Circular, N-BK7 Optical Glass

Diameter Tolerance +/- 0.125 mm Thickness Tolerance +/- 0.125 mm Surface Accuracy 1.0-3.0 mm thickness ≤ 5λ per inch4.76-12.7 mm thickness ≤ 2λ per inch Surface Quality 60-40 Scratch-Dig or better Parallelism <15' Edges Fine ground and safety beveled* Clear Aperture 90% *parts under 25.4mm in diameter may not have beveled edges Commercial windows are used for sight glasses, instrument windows, beamsplitter substrates, vacuum windows, welding window substrates. Esco carries a complete inventory of circular commercial optical windows of N-BK-7 Optical Glass. Windows are polished both sides with ground edges. Don't see a part that matches exactly what you need, perhaps you'd like to modify a dimension or add a coating?  Use our fast online quote tool to find out what a custom part would cost.