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Knight Optical(UK) Ltd - sales@knightoptical.co.uk - +44 (0)1622 859444

Metallic neutral density filters

What are you looking for in Stock?

Metallic Neutral Density filters comprise a thin metallic layer on a borosilicate glass or UV grade fused silica polished window.  Metallic ND filters attenuate the light by reflection and thus avoid the possible heating issues with glass and gelatine neutral density filter types.  However care must be taken to ensure the reflected light does not cause problems.  

Our stock range of visible/IR range of Metallic Neutral Density Filters are coated on low-expansion borosilicate glass substrates and cover the range from 350-2500nm. Our UV range of Metallic Neutral Density Filters are coated on UV grade fused silica and therefore cover the useful UV region down to 170nm.

All Metallic ND Filters are supplied with a copy of the spectral transmittance scan taken on a filter at the time of the production coating.  We stock uncoated borosilicate or equivalent and UV fused silica substrates so custom Metallic filters can be supplied to your specific request. Please contact our technical sales team with your requirements.

Material:  Borosilicate (LEGB) or equivalent UV fused silica
Optical density:  @550nm
Diameter:  +0.0 / -0.2 mm
Length / width: ± 0.2 mm
Thickness: ± 0.1 mm
Flatness:   <2λ (over 90% of dia)
Parallelism:   <1 arc min.
Surface quality: <40-20 scratch/dig


  • Mounting of diameters and squares.
  • Antireflective coatings can be applied to one or both faces for improved transmission.
  • Cutting down or edged to special shapes and sizes at short notice.
  • Larger sizes are available.
  • Custom OD values to your specific requirement.
  • Available in sets, supplied in a wooden storage box for research and laboratory use.

Stock Optics

Get a Custom Quote

Part No. RangeDensity @ 550nmTrans (%) @ 550nmThick
Material Price
FNM00325 Download Vis/NIR0.0393225Uncoated Borosilicate £8.40
FNM00350 Download Vis/NIR0.039325050Uncoated Borosilicate £17.45
FNM0125 Download Vis/NIR0.179225Borosilicate £17.70
FNM0150 Download Vis/NIR0.17925050Borosilicate £26.70
FNM0225 Download Vis/NIR0.263225Borosilicate £17.70
FNM0250 Download Vis/NIR0.26325050Borosilicate £26.70
FNM0325 Download Vis/NIR0.350225Borosilicate £17.70
FNM0350 Download Vis/NIR0.35025050Borosilicate £26.70
FNM0425 Download Vis/NIR0.440225Borosilicate £17.70
FNM0450 Download Vis/NIR0.44025050Borosilicate £26.70
FNM0525 Download Vis/NIR0.532225Borosilicate £17.70
FNM0550 Download Vis/NIR0.53225050Borosilicate £26.70
FNM0625 Download Vis/NIR0.625225Borosilicate £17.70
FNM0650 Download Vis/NIR0.62525050Borosilicate £26.70
FNM0725 Download Vis/NIR0.719225Borosilicate £17.70
FNM0750 Download Vis/NIR0.71925050Borosilicate £26.70
FNM0825 Download Vis/NIR0.816225Borosilicate £17.70
FNM0850 Download Vis/NIR0.81625050Borosilicate £26.70
FNM1025 Download Vis/NIR110225Borosilicate £17.70
FNM1050 Download Vis/NIR11025050Borosilicate £26.70
FNM1525 Download Vis/NIR1.53.2225Borosilicate £17.70
FNM1550 Download Vis/NIR1.53.225050Borosilicate £26.70
FNM2025 Download Vis/NIR21225Borosilicate £17.70
FNM2050 Download Vis/NIR2125050Borosilicate £26.70
FNM3025 Download Vis/NIR30.1225Borosilicate £17.70
FNM3050 Download Vis/NIR30.125050Borosilicate £26.70
FNU00325 Download UV0.0393225Uncoated UV grade fused silica £19.80
FNU00350 Download UV0.039325050Uncoated UV grade fused silica £32.00
FNU0125 Download UV0.179225UV grade fused silica £37.30
FNU0150 Download UV0.17925050UV grade fused silica £54.95
FNU0225 Download UV0.263225UV grade fused silica £37.30
FNU0250 Download UV0.26325050UV grade fused silica £54.95
FNU0325 Download UV0.350225UV grade fused silica £37.30
FNU0350 Download UV0.35025050UV grade fused silica £54.95
FNU0425 Download UV0.440225UV grade fused silica £37.30
FNU0450 Download UV0.44025050UV grade fused silica £54.95
FNU0525 Download UV0.532225UV grade fused silica £37.30
FNU0550 Download UV0.53225050UV grade fused silica £54.95
FNU0625 Download UV0.625225UV grade fused silica £37.30
FNU0650 Download UV0.62525050UV grade fused silica £54.95
FNU0725 Download UV0.719225UV grade fused silica £37.30
FNU0750 Download UV0.71925050UV grade fused silica £54.95
FNU0825 Download UV0.816225UV grade fused silica £37.30
FNU0850 Download UV0.81625050UV grade fused silica £54.95
FNU1025 Download UV110225UV grade fused silica £37.30
FNU1050 Download UV11025050UV grade fused silica £54.95
FNU1525 Download UV1.53.2225UV grade fused silica £37.30
FNU1550 Download UV1.53.225050UV grade fused silica £54.95
FNU2025 Download UV21225UV grade fused silica £37.30
FNU2050 Download UV2125050UV grade fused silica £54.95
FNU3025 Download UV30.1225UV grade fused silica £37.30
FNU3050 Download UV30.125050UV grade fused silica £54.95

Get a Custom Quote

Get in touch

Our Multi-Lingual Sales Team are here to help with your requirments:

UK +44 (0)1622 859444
UK +44 (0)1622 850614
UK +44 (0)1622 851078
+1 401 583 7846

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We are able to ship to most countries at good rates, please click here for more info.

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