Absorptive Neutral Density Filters

These absorptive neutral density filters (unlike metallic filters) are manufactured
from a family of Schott glasses exhibiting various internal absorption coefficients.
By using three different glasses (each with a unique absorption) that have spectrally
flat absorption coefficients and by differing the filter thicknesses, we are able to
manufacture a progressively more absorptive series of neutral density filters. All data

Specifications
■ Substrate: NG11, NG4,
and NG9 (Schott)
■ Diameter (mm):
25.0 +0.0/-0.25
■ Clear Aperture: 90% OD
■ Surface Flatness: λ Over 95%
■ Surface Quality:
60-40 Scratch-Dig
■ Parallelism: 10arcsec for Ø1"
3arcmin for Ø1/2"

■ Ideal for Low Power Applications
■ Absorptive Glass Reduces Multiple Reflections
■ Optical Density Tolerances < ±5% @ 633 nm