Schott Glass Metallic Neutral Density Filters

Made with Inconel® metallic coatings on glass substrates, these moderately priced ND filters provide uniform attenuation of low and medium power beams across a broad spectral range.

Economy neutral density filters
1 inch diameter ﬁts mirror mounts and ﬁlter wheels
Broad 400 to 2000 nm wavelength range
Suitable for use with moderate powered lasers
Available in convenient kits

See All Features

Description	Compatibility	Price
5230 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 0.04 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5231 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 0.1 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5232 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 0.2 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5233 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 0.3 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5234NF Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 0.4 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5235 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 0.5 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5240 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 1.0 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5241 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 1.5 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5242 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 2.0 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46
5243 Schott Borofloat Glass Metallic ND FiltersNeutral Density Filter, 2.5 Optical Density, 1.0 in. Diameter	UNIVERSAL	$46

Features

Finely Control Beam Attenuation

Made with Inconel® metallic coatings on glass substrates, these ND filters provide spectrally uniform attenuation over the wavelength range from 0.4 to 2.0 µm. The reflective nature of the coatings helps reduce thermal effects when these filters are used with moderate-power lasers. Filters may be used individually, or combined in series, to obtain any desired density from 0.04 to 2.5.

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.

Filter Kits

The 5247NF, 5248 and 5249NF Neutral Density (ND) Filter Sets contain the same filters that we use in our ND-filter wheels. The 5247NF set contains six metallic, borofloat filters of OD 0.04, 0.5, 1.0. 1.5. 2.0 and 2.5. The 5248 set contains six metallic, borofloat filters of OD 0.04, 0.1, 0.2, 0.3, 0.4 and 0.5. The 5249 set contains ten metallic, borofloat filters of OD 0.04, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0 and 2.5. Filter kits provide convenience and cost savings.

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.

Borofloat® 33 Substrates

Borofloat 33 is a high quality borosilicate glass that offers low thermal expansion and high thermal shock resistance. Its material properties and moderate cost make Borofloat 33 an ideal substrate for general purpose applications. For more information, please see our Optical Materials technical note.