TECHSPEC® VIS-NIR Neutral Density (ND) Filters feature a constant transmission from 350 – 1100nm and are used to attenuate many broadband visible and NIR light sources. Optical Densities are additive allowing these filters to be stacked to achieve custom optical density values. For example, stacking filters with OD values of 0.2 and 2.0 yields a resultant optical density of 2.2. TECHSPEC® VIS-NIR Neutral Density (ND) Filters are available in a range of 12.5, 25, and 50mm diameters as well as a 50 x 50mm square option in various increments of optical densities from 0.1 to 3.0. These filters are ideal for use in laser and photometer applications, where excessive power can cause damage or inaccurate results.
Note: Low optical density filters (0.1, 0.15, and 0.2 OD) are coated with thin layers of Inconel and their performance may shift overtime. To prolong the lifetime of these filters, we recommend using non-contact cleaning methods (such as compressed air) to prevent damage to the coating and avoiding the use of these filters in humid environments to prevent oxidation.