Optical Crown Glass Metallic Neutral Density Filters

Our metallic neutral density coatings provide broadband attenuation for low power applications. The coating is deposited on one side of a cost effective B 270 optical glass substrate, providing excellent performance in the visible and near-infrared.

Cost effective optical crown glass
Broadband attenuation, visible to near IR
Metallic neutral density coating
For lower power applications
Available in convenient kits

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Showing 10 of 22 total products

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Description	Compatibility	Size	Optical Density	Optical Density Tolerance	Avail.	Price
FBR-ND004ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 0.04 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	0.04	±2.5% @ 632.8 nm	In Stock	$42
FBR-ND01ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 0.1 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	0.1	±8% @ 632.8 nm	In Stock	$61
FBR-ND02ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 0.2 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	0.2	±7% @ 632.8 nm	In Stock	$61
FBR-ND03ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 0.3 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	0.3	±6% @ 632.8 nm	In Stock	$61
FBR-ND04ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 0.4 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	0.4	±5% @ 632.8 nm	In Stock	$61
FBR-ND05ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 0.5 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	0.5	±4% @ 632.8 nm	In Stock	$61
FBR-ND10ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 1.0 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	1	±4% @ 632.8 nm	In Stock FREE 2-day shipping on thousands of products on Newport.com Learn More	$61
FBR-ND15ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 1.5 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	1.5	±4% @ 632.8 nm	In Stock FREE 2-day shipping on thousands of products on Newport.com Learn More	$61
FBR-ND20ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 2.0 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	2	±4% @ 632.8 nm	In Stock FREE 2-day shipping on thousands of products on Newport.com Learn More	$61
FBR-ND25ND Filter, Metallic, Optical Crown Glass, 25.4 mm, 2.5 OD at 632.8 nm	UNIVERSAL	Ø25.4 mm	2.5	±4% @ 632.8 nm	Contact Us FREE 2-day shipping on thousands of products on Newport.com Learn More	$61

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Specifications

Wavelength Range
400-1200 nm
Angle of Incidence
0°
Material
B270 Optical Crown Glass or Equivalent
Damage Threshold
30 W/cm² CW, typical; not recommended for pulsed laser use
Size Tolerance
+0/-0.50 mm
Thickness
3.0 mm
Thickness Tolerance
±0.25 mm

Surface Flatness
≤5λ at 632.8 nm over the clear aperture
Surface Quality
60-40 scratch-dig
Clear Aperture
≥central 80% of dimensions
Wedge
≤5 arc min
Chamfers
0.25–0.76 mm face width
Chamfers Angle Tolerance
45° ±15°
Cleaning
See How to Clean Optics

Features

Finely Control Beam Attenuation

Filters from this product family may be used individually, or combined in series, to obtain any desired density from 0 to 7 in steps of 0.1OD. Please note that stacking an excessive number of filters may lead to numerous unwanted back reflections. All filters are shipped with a transmission curve.

ND Filter Sets

The FB-ND Optical Crown Glass Metallic Neutral Density Filter Set is a set of eight 25.4 mm diameter optical crown glass metallic ND filters of OD 0.04, 0.1, 0.3, 0.5, 1.0, 2,0 and 3.0, which includes a wood case. Our metallic neutral density coatings provide broadband attenuation for low power applications. The coating is deposited on one side of a cost-effective B 270 optical glass substrate, providing excellent performance in the visible and NIR. Filter kits provide convenience and cost savings. All filters are shipped with a transmission curve.

Additive Optical Densities

Optical density (OD) is given by the relationship: OD = -log(T) or T = 10^(-OD) where T is transmittance (0≤T≤1). Optical Density, unlike transmittance, is additive. When multiple filters are stacked, the total density is easily found by adding up the densities of each filter in the series. For example to achieve desired transmittance of 8%, first calculate the equivalent density (OD = -log(0.08) = 1.097 ≅ 1.1), then find a combination of filters that adds to the desired number, such as a combination of an OD1 filter and an OD0.1 filter.

Proper Orientation

To prevent unwanted interference from etalon effects, filters should be angled slightly with respect to the incident beam. To minimize back reflections, the filter should be oriented with the coated metallic surface facing the incident beam. Any light reflected from the uncoated second surface will pass through the metallic coating first, which will greatly attenuate unwanted back reflections.