Metallic neutral density filters These Metallic Neutral Density Filters attenuate light through reflection rather than absorption as in the glass type of neutral density filter. Metallic Neutral Density Filters consist of a thin layer of nickel-chromium alloy vacuum-deposited on a glass substrate. This gives excellent neutrality and very accurate attenuation across the surface. About half the rejected light is absorbed and the remainder reflected, so these filters can also be used as beamsplitters. The visible/IR range of Metallic Neutral Density Filters are on low-expansion borosilicate glass substrates and covers the range 350-2500nm. Our UV range of Metallic Neutral Density Filters is on synthetic fused silica and extend the useful UV range down to about 170nm. Please note that the density of all filters is specified at 550nm, but in the UV it can be up to 40% higher-see curves. All filters are supplied with a copy transmittance scan taken on a filter from the same production run.
Knight Optical > Filters > Neutral density filters - Metallic type > Visible/IR-Grade 25 diameter (mm) This is the section containing 25 diameter (mm). 50 x 50 (mm) This is the section containing 50 x 50 (mm). Only UK and EU customers are charged VAT at 17.5%, customers outside the EU and EU customers based outside the UK who have a valid EU VAT number will not be charged VAT Bulk Discounts! Where (B) appears next to a price below, bulk prices are available, click the (B) button to view! Knight Optical > Filters > Neutral density filters - Metallic type > Visible/IR-Grade
Specification   Material: LEBG, UV fused silica Material Data: (see materials section) Optical Density : @550nm Diameter: +0.0 / -0.2 mm Length / width: ± 0.2 mm Thickness: ± 0.1 mm Surface quality: <60-40
Specific requirements We can manufacture Metallic Neutral Density Filters to any size at short notice, so if your requirements are not listed please contact us by telephone / fax or email: stockrequirement@knightoptical.co.uk Options available   · Cutting down or edged to special shapes and sizes   · Mounting (25mm dia only) Technical Data Sheets Set of transmittance curves are available for each filter on request, please specify type. See also Glass neutral density filters Gelatin neutral density filters See also FNM0100 Visible/IR 25mm dia. set (13 filters) FNM0200 Visible/IR 50 x 50mm set (13 filters) FNU0100 UV 25mm dia. set (11 filters) FNU0200 UV 50 x 50mm set (11 filters) For storage boxes (see accessories)