K9L (N-BK7) Double Concave DCV Lens

Common Specification

Material K9L or BK7
Surface quality 40-20 scratch & dig (MIL-PRF-13830B)
Clear aperture 90% of the diameter
Diameter tolerance +0.00, -0.12 mm
Thickness tolerance ±0.2 mm
Surface irregularity λ/8 @ 633 nm
Concentricity 3 arcmin