Absorptive Neutral Density Filter, 12.7 mm, 0.8 OD at 546.1 nm

The FR-OD80 Absorptive Neutral Density Filter is a 1/2 inch (12.7 mm) diameter absorptive neutral density filter that has an Optical Density of 0.8 at 546.1 nm, and provides broadband attenuation for the visible to near-infrared region. This filter is precision polished for demanding research or OEM applications. The filter's Optical Density is permanently marked on the filter and is shipped with a transmission curve. Our unique assortment of filters permits easy selection of any desired density from 0 to 8 with 0.1 OD resolution by using individual filters or a combination of no more than two filters. The total filter set range is 0 to 8 OD. Optical density (OD) is defined by the relationship: OD = -log(T) or T = 10^-OD, where T is transmission (0=T=1). The density of a series of filters, unlike transmission, is additive. Custom densities can therefore be obtained by stacking filters, however stacking an excessive number of filters can lead to numerous unwanted back reflections. Due to the absorptive nature of the filter glass, use with high power lasers should be avoided. Power levels less than 30 W/cm² are advised.