This attenuation filter is used to optimize measurements of highly reflective parts and helps produce good fringe contrast. The filter is positioned between the test part and a standard transmission flat.
Specifications: Quality: ≤ ?/10 Transmitted wavefront (PVr) Transmittance (4 in. filter) : 20 ± 4% @ 10° angle of incidence @ ?=632.8 nm through the pelicle
